//1496 阶乘的和 #include<iostream> #include<cstdio> #include<cstring> #include<cmath> using namespace std; long long use(long long n){ int s=1; for(int i=1;i<=n;i++){ s*=i; } return s; } int main(){ int zoom=0,n=0; cin>>n; for(int i=1;i<=n;i++){ zoom+=use(i); } cout<<zoom; return 0; }