#include<iostream> #include<vector> using namespace std; int main(){ int n; cin>>n; int fac[100]={0}; int sum[100]={0}; fac[0]=1; int len=1; for(int i=1;i<=n;i++){ int carry=0; for(int j=0;j<100;j++){ int temp=fac[j]*i+carry; fac[j]=temp%10; carry=temp/10; }int ad_carry=0; for(int j=0;j<100;j++){ int temp=sum[j]+fac[j]+ad_carry; sum[j]=temp % 10; ad_carry=temp/10; } }int pos=99; while(pos>0&&sum[pos]==0)pos--; for(int i=pos;i>=0;i--){ cout<<sum[i]; }cout<<endl; return 0; }