diff --git a/circuits/bigint.circom b/circuits/bigint.circom
index 5e50701..77f3a33 100644
--- a/circuits/bigint.circom
+++ b/circuits/bigint.circom
@@ -614,7 +614,8 @@ template BigAddModP(n, k){
     sub.a[k] <== add.out[k];
     sub.b[k] <== 0;
     
-    sub.out[k] === 0;
+    // the following constraint can be implied
+    // sub.out[k] === 0;
     for (var i = 0; i < k; i++) {
         out[i] <== sub.out[i];
     }