有没有大佬帮我看看，两个WA

#include<iostream>
using namespace std;

int main(){
    int n;cin>>n;
    int ans=0;
    for (int i =1;i<=n;i++)
    {
        int a=1;
        for (int j = 1;j<=i;j++)
        {
            a*=j;
        }
        ans+=a;
    }
    cout<<ans; 
    
}