diff --git a/src/main/java/me/hatter/math/ModularInv.java b/src/main/java/me/hatter/math/ModularInv.java
index bd7c7f2..11b1f6d 100644
--- a/src/main/java/me/hatter/math/ModularInv.java
+++ b/src/main/java/me/hatter/math/ModularInv.java
@@ -26,13 +26,16 @@ public class ModularInv {
             for (long j = 1; j < 10000; j++) {
                 BigInteger a = BigInteger.valueOf(i);
                 BigInteger p = BigInteger.valueOf(j);
+                // gcd(a, p) = 1
                 if (!a.gcd(p).equals(BigInteger.ONE)) {
                     continue;
                 }
+                // a^-1 mod p
                 BigInteger x = a.modInverse(p);
                 BigInteger y = modularInv(a, p);
-                System.out.println(Arrays.asList(a, p, a.modInverse(p), modularInv(a, p)));
-                if (!y.equals(x)) {
+                BigInteger z = a.modPow(Phi.phi(p).subtract(BigInteger.ONE), p);
+                System.out.println(Arrays.asList(a + "^-1 mod " + p, x, y, z));
+                if (!y.equals(x) || !y.equals(z)) {
                     throw new RuntimeException();
                 }
             }