#include<stdio.h>
int main()
{
    int (fact n);
    int n,i;
    int fact=1;
    scanf("%d",&n);
    if(n<0)
    {
      printf("Invalid Input"); 
      return 0;
    }
    for(i=1;i<=n;i++)
    {
        fact*=i;
    }
    printf("%d",n,fact(n))
    return 0;
}