diff --git a/library/math/mod_int.hpp b/library/math/mod_int.hpp
index 81052c7d..a2fa8818 100644
--- a/library/math/mod_int.hpp
+++ b/library/math/mod_int.hpp
@@ -8,12 +8,5 @@ struct mint {
   mint operator+(mint b) { return x - mod + b.x; }
   mint operator-(mint b) { return x - b.x; }
   mint operator*(mint b) { return ll(x) * b.x % mod; }
-  mint operator/(mint b) {
-    int m = mod, u = 1, v = 0;
-    while (m)
-      u = exchange(v, u - b.x / m * v),
-      b.x = exchange(m, b.x % m);
-    assert(b.x == 1);
-    return *this * u;
-  }
+#include "mod_int_division.hpp"
 };
diff --git a/library/math/mod_int_division.hpp b/library/math/mod_int_division.hpp
new file mode 100644
index 00000000..a043afe4
--- /dev/null
+++ b/library/math/mod_int_division.hpp
@@ -0,0 +1,9 @@
+#pragma once
+mint operator/(mint b) {
+  int m = mod, u = 1, v = 0;
+  while (m)
+    u = exchange(v, u - b.x / m * v),
+    b.x = exchange(m, b.x % m);
+  assert(b.x == 1);
+  return *this * u;
+}