diff --git a/main.cpp b/main.cpp
index 7e40a09..f6de8cf 100644
--- a/main.cpp
+++ b/main.cpp
@@ -10,25 +10,30 @@ struct Input {
     size_t bin_count;
 };
 
-Input input_data() {
-    Input in;
+Input input_data(istream& in, bool prompt) {
+    Input inp;
     size_t number_count;
-    cerr << "Enter number count: ";
+    if (prompt){
+        cerr << "Enter number count: ";
+    }
     cin >> number_count;
-
-    in.numbers.resize(number_count);
-    cerr << "Enter numbers: ";
+    inp.numbers.resize(number_count);
+    if (prompt){
+                cerr << "Enter numbers: ";
+        }
     for (size_t i = 0; i < number_count; i++) {
-        cin >> in.numbers[i];
+        cin >> inp.numbers[i];
     }
 
-    cerr << "Enter bin count: ";
-    cin >> in.bin_count;
-    return in;
+    if (prompt) {
+            cerr << "Enter bin count: ";
+    }
+    cin >> inp.bin_count;
+    return inp;
 }
 
 int main() {
-    auto in = input_data();
+    auto in = input_data(cin, true);
     auto bins = make_histogram(in.numbers, in.bin_count);
     show_histogram_svg(bins);
     return 0;