diff --git a/src/P2822/P2822.cpp b/src/P2822/P2822.cpp
index 9fe8d80..51ae042 100644
--- a/src/P2822/P2822.cpp
+++ b/src/P2822/P2822.cpp
@@ -7,6 +7,7 @@ using ull = unsigned long long;
 
 static ull t, k, n, m, ans;
 static std::map<ull,ull> fact_map;
+static std::map<std::pair<ull,ull>,ull> C_map;
 
 static ull fact(const ull n)noexcept{
     if(n==0)return 1;
@@ -14,14 +15,18 @@ 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%k*i%k);
+        ret*=i;
     }
     fact_map.insert({n,ret});
     return ret;
 }
 
 static ull C(const ull n, const ull m)noexcept{
-    return fact(n)/(fact(m)*fact(n-m)%k);
+    const auto it = C_map.find({n,m});
+    if(it!=C_map.end())return (*it).second;
+    const ull ret = (fact(n))/(fact(m)*fact(n-m));
+    C_map.insert({{n,m},ret});
+    return ret;
 }
 
 int main(){