#include <stdio.h>


int  q(int s)

{

if(s==1)

{

return s;

}

else

{

return s*q(s-1);

}



}



void main()

{

freopen("input.txt","r",stdin);

freopen("output.txt","w",stdout);


int n;

int ap;


scanf("%d",&n);


ap=q(n);


printf("%d\n",ap);

}



맞다면 이렇게 푸셈