#include<stdio.h>int main(){ int fac(int n); int n; int y; scanf("%d",&n); y=fac(n); printf("%d%d",n,y); return 0;}int fac(int n);{ int f; if(n<0) printf("date error"); else if(n==1) f=1; else f=fac(n-1)*n; return(f);}