diff --git a/test.c b/test.c
index 0118cc8..6b61525 100644
--- a/test.c
+++ b/test.c
@@ -5,7 +5,11 @@
 
 int sum(int n)
 {
-    return ((n + 1) * n) / 2;
+    int sum = 0;
+    for(int i = 1; i <= n; i++) {
+        sum += i;
+    }
+    return sum;
 }
 
 void usage(const char* app_name, const char* err_string)