101

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