diff --git a/main.cpp b/main.cpp
index 3f7145b..40b9768 100644
--- a/main.cpp
+++ b/main.cpp
@@ -11,26 +11,26 @@ struct Input {
 };
 
 Input
-input_data(){
+input_data(istream& stream){
     size_t number_count;
     cerr << "Enter number count:" << endl;
-    cin >> number_count;
+    stream >> number_count;
     Input in;
     in.numbers.resize(number_count);
     vector<double> numbers(number_count);
     cerr << "Enter numbers:" << endl;
     for (size_t i = 0; i < number_count; i++) {
-        cin >> in.numbers[i];
+        stream >> in.numbers[i];
     }
     cerr << "Enter bin count:" << endl;
-    cin >> in.bin_count;
+    stream >> in.bin_count;
     return in;
 }
 
 
 int
 main() {
-    auto in = input_data();
+    auto in = input_data(cin);
     auto bins = make_histogram(in.numbers, in.bin_count);
     show_histogram_svg(bins);
     return 0;