diff --git a/src/P2822/P2822.cpp b/src/P2822/P2822.cpp
index d452170..9fe8d80 100644
--- a/src/P2822/P2822.cpp
+++ b/src/P2822/P2822.cpp
@@ -14,7 +14,7 @@ static ull fact(const ull n)noexcept{
     if(it !=  fact_map.end())return (*it).second;
     ull ret {1};
     for(ull i{2};i<=n;i++){
-        ret=(ret*i)%k;
+        ret=(ret%k*i%k);
     }
     fact_map.insert({n,ret});
     return ret;