diff --git a/Minkowski_sum_2/test/Minkowski_sum_2/test_approx_offset.cpp b/Minkowski_sum_2/test/Minkowski_sum_2/test_approx_offset.cpp
index 41e9241135c..d378a271366 100644
--- a/Minkowski_sum_2/test/Minkowski_sum_2/test_approx_offset.cpp
+++ b/Minkowski_sum_2/test/Minkowski_sum_2/test_approx_offset.cpp
@@ -58,7 +58,7 @@ int main (int argc, char* argv[])
     return -1;
   }
 
-  unsigned int i = 1;
+  int i = 1;
   while (i < argc) {
     // Read the polygon from the input file.
     Polygon_2   pgn;