1 files changed, 3 insertions, 0 deletions
diff --git a/math/shortModInv.cpp b/math/shortModInv.cpp
new file mode 100644
index 0000000..747eb7a
--- /dev/null
+++ b/math/shortModInv.cpp
@@ -0,0 +1,3 @@
+ll inv(ll a, ll b){ // a^{-1} mod b
+    return 1 < a ? b - inv(b % a, a) * b / a : 1;
+}
+\ No newline at end of file