1#include<stdio.h>
2fact(int i, int k){
3 k=k*i;
4 i--;
5 if(i==0){
6 return k;
7 }
8 else{
9 fact(i, k);
10 }
11}
12int main()
13{
14 int k = 1, i, factorial;
15 scanf("%d",&i);
16 factorial = fact(i, k);
17 printf("%d\n",factorial);
18 return 0;
19}