diff --git a/main.cpp b/main.cpp
index 5917340..981a958 100644
--- a/main.cpp
+++ b/main.cpp
@@ -14,7 +14,7 @@ struct Input {
 };
 
 Input
-input_data() {
+input_data(istream& in) {
     Input in;
     cerr << "Enter number count: ";
     cin >> in.number_count;
@@ -38,7 +38,7 @@ input_data() {
 
 int main()
 {
-    auto in = input_data();
+    auto in = input_data(cin);
     auto bins = make_histogram(in.numbers, in.bin_count, in.number_count, in.max_count);
     vector<double> test;
     show_histogram_svg(bins, in.max_count, in.bin_count, test);