#include <fstream.h>
int main(){
	unsigned long p,i,aux,k;
        ifstream f("fact.in");
	ofstream g("fact.out");
	f>>p;
	if(p>=1){
		k=0;
		i=5;
		while(k<p){
			if(i%5==0){
				aux=i;
				while(aux%5==0){
					aux/=5;
					k++;
				}
			}
			i+=5;
		}
		g<<i-5;
	}else
		g<<1;
	return 0;
}