diff --git a/src/main/java/ru/lionarius/IntegralCalculator.java b/src/main/java/ru/lionarius/IntegralCalculator.java
index 8cfdd02..b1f1243 100644
--- a/src/main/java/ru/lionarius/IntegralCalculator.java
+++ b/src/main/java/ru/lionarius/IntegralCalculator.java
@@ -1,11 +1,8 @@
 package ru.lionarius;
 
 import java.util.ArrayList;
-import java.util.concurrent.ExecutionException;
-import java.util.concurrent.ExecutorService;
-import java.util.concurrent.Executors;
-import java.util.concurrent.Future;
-import java.util.concurrent.atomic.AtomicLong;
+import java.util.concurrent.*;
+import java.util.concurrent.locks.ReentrantLock;
 import java.util.function.BiConsumer;
 import java.util.function.Function;
 
@@ -107,24 +104,75 @@ public class IntegralCalculator {
 
         this.callProgressCallback(0, n);
 
+        var remainder = n % parallelism;
+        var partitionSize = n / parallelism;
+        var currentStart = 0L;
+
         var sum = (function.apply(lowerBound) + function.apply(upperBound)) / 2;
+
         final var futures = new ArrayList<Future<Double>>();
+        final var semaphore = new Semaphore(2);
+        final var lock = new ReentrantLock();
+        final var latch = new CountDownLatch(parallelism);
+
+        var times = new long[parallelism];
+        var totalProgress = new long[]{0L};
         for (var i = 0; i < parallelism; i++) {
-            final var order = i;
+            final var start = currentStart;
+            final var end = currentStart + partitionSize + (remainder > 0 ? 1 : 0);
+            if (remainder > 0)
+                remainder--;
+            currentStart = end;
+
+            final var innerI = i;
+
             futures.add(executor.submit(() -> {
                 var partitionSum = 0.0;
-                for (var j = order; j < n; j += parallelism) {
-                    partitionSum += function.apply(lowerBound + h * j);
+                try {
+                    semaphore.acquire();
 
-                    this.callProgressCallback(j, n);
+                    for (var j = start; j < end; j++) {
+                        partitionSum += function.apply(lowerBound + h * j);
+
+                        lock.lock();
+                        try {
+                            totalProgress[0] += 1;
+                            this.callProgressCallback(totalProgress[0], n);
+                        } finally {
+                            lock.unlock();
+                        }
+                    }
+
+                    lock.lock();
+                    try {
+                        times[innerI] = System.nanoTime();
+                    } finally {
+                        lock.unlock();
+                    }
+                } finally {
+                    semaphore.release();
                 }
+                
+                latch.countDown();
 
                 return partitionSum;
             }));
         }
 
+        latch.await();
+
         for (var future : futures) {
-            sum += future.get();
+            sum += future.resultNow();
+        }
+
+        var minimumTime = Long.MAX_VALUE;
+        for (var time : times) {
+            if (time < minimumTime)
+                minimumTime = time;
+        }
+
+        for (var i = 0; i < parallelism; i++) {
+            System.out.printf("Thread %d took %.6fms%n", i, (times[i] - minimumTime) / 1_000_000.0);
         }
 
         sum *= h;
diff --git a/src/main/java/ru/lionarius/Main.java b/src/main/java/ru/lionarius/Main.java
index 70f0248..c6fbd09 100644
--- a/src/main/java/ru/lionarius/Main.java
+++ b/src/main/java/ru/lionarius/Main.java
@@ -9,25 +9,28 @@ public class Main {
         Function<Double, Double> function = x -> Math.sin(x) * x;
         var lowerBound = 0.0;
         var upperBound = 1.0;
-        double[] accuracies = {0.0001, 0.00001, 0.0000001, 0.000000001, 0.000000001};
+        double[] accuracies = {0.0001, 0.00001, 0.0000001, 0.000000005};
         
-        var executor = Executors.newCachedThreadPool();
+        var executor = Executors.newFixedThreadPool(Runtime.getRuntime().availableProcessors());
         for (final var accuracy : accuracies) {
             var calculator = new IntegralCalculator(
-                    accuracy
+                    accuracy,
+                    (i, n) -> {
+                        if (i % (n / 15) == 0)
+                            System.out.printf("[%s] Progress %f%%%n", Thread.currentThread().getName(), i / (double) n * 100.0);
+                    }
             );
 
             var startTime = System.nanoTime();
             
             double value = 0;
             try {
-                value = calculator.calculate(function, lowerBound, upperBound, executor, 1);
+                value = calculator.calculate(function, lowerBound, upperBound, executor, 8);
             } catch (ExecutionException e) {
                 System.err.println("Error calculating integral: " + e.getMessage());
             }
             catch (InterruptedException e) {
                 System.err.println("Thread interrupted: " + e.getMessage());
-                executor.shutdown();
             }
 
             var totalTime = System.nanoTime() - startTime;