Files
2023-08-03 09:22:52 +08:00

17 lines
194 B
C++

#include<cstdio>
using namespace std;
int main()
{
int n;
long long ans=0,times=1;
scanf("%d",&n);
for(int i=1;i<=n;i++)
{
times*=i;
ans+=times;
}
printf("%lld\n",ans);
return 0;
}