1 #include<cstdio>
 2 int n,a,fz[50000],ans[50000]={1,1};
 3 int main(){
 4     scanf("%d",&n);
 5     for(int i=1;i<=n;i++)
 6     for(int j=1;j<=ans[0];j++){
 7         ans[j]=ans[j]*i+fz[j];fz[j]=0;
 8         if(ans[j]>9){
 9             fz[j+1]+=ans[j]/10;
10             ans[j]%=10;
11             if(j==ans[0]) ++ans[0];
12         }
13     }
14     for(int i=ans[0];i>0;i--) printf("%d",ans[i]);
15     printf("\n");
16     return 0;
17 }