diff --git a/main.js b/main.js
index 4dbf947..33b5ad1 100644
--- a/main.js
+++ b/main.js
@@ -8,7 +8,7 @@ function evaluate() {
 	const result = document.querySelector("#result");
 
 	const m = BigInt(modulus.value);
-	if (m === 0n) {
+	if (m <= 0n) {
 		const e = Error("invalid modulus")
 		result.value = e;
 		console.log(e);