#include <stdio.h>
#include <math.h>

int factorial(int N) {

  int f=1,i;
  
  for (i=2;i<=N;i++)
    f*=i;
  
  return f;

}

main() {

  int N;

  printf("Enter an integer : ");
  scanf("%d",&N);
  
  printf("%d! = %d\n", N, factorial(N));

}


