diff --git a/src/main.cu b/src/main.cu
index c222bb895e5933e78f4e9b708f43947e486b8949..21235329002880ddb8020d0a91fac68086bf3ba7 100644
--- a/src/main.cu
+++ b/src/main.cu
@@ -182,10 +182,9 @@ void radix_sort(uint64_t *arr, int n) {
   cudaFree(count);
 }
 
-int main(void)
+int main(int argc, char **argv)
 {
-
-  int N = 5000;
+  int N = atoi(argv[1]);
   uint64_t *arr;
 
   arr = (uint64_t*)malloc(N * sizeof(uint64_t));