text: #include <stdio.h>
  #include <stdlib.h>
  int fatorial (int N)
  {
      int Fat = 1;
      while(N != 0)
      {
              Fat = Fat *N;
              N--;
      }
      return(Fat);
  }
  int main (void)
  {
  	int N;
  	scanf("%d",&N);
  	if(N=!0)
  	{
  	    fatorial(N);
  	    printf("%d\n",fatorial(N));
  	}
  	else
  	{
  	    printf("0");
      }
  	return 0;
  }
  