diff --git a/cs-project3.cpp b/cs-project3.cpp
index f046d8e..6f1606f 100644
--- a/cs-project3.cpp
+++ b/cs-project3.cpp
@@ -13,22 +13,22 @@ struct Input {
 };
 
 Input
-input_data() {
+input_data(istream& inn) {
     Input in;
     size_t number_count;
-    cin >> number_count;
+    inn >> number_count;
     in.numbers.resize(number_count);
     for (size_t i = 0; i < number_count; i++) {
-        cin >> in.numbers[i];
+        inn >> in.numbers[i];
     }
     size_t bin_count;
-    cin >> in.bin_count;
+    inn >> in.bin_count;
     return in;
 }
 
 
 int main() {
-    Input in = input_data();
+    Input in = input_data(cin);
     auto bins = make_histogram(in.numbers, in.bin_count);
     show_histogram_svg(bins);
     return 0;