#include<stdio.h>
#include<stdlib.h>
int main()
{
  int n, i, f;


  scanf("%d", &n);
if(0 <= n && n <=12)
{
  f = 1;
for(i=1;i<=n;i++)
{

    f = f * i;

  }

  printf("%d \n",f);
}
else
{
    printf("valor invalido \n");
}

return(0);

}