#include<fstream.h>
#include<iostream.h>
long int nr;
short int ok;
int main(){
long long int i,j,p,r;
ifstream f("fact.in");
ofstream g("fact.out");
f>>p;
if(p==0){g<<"1";}
i=0;
ok=1;
while(ok){
	if(nr==p){
		break;}
	i=i+5;
	r=0;
	j=i;
	while(j%5==0){
		j=j/5;
		r++;}
	if(i%25!=0){
		nr++;}
	if(i%25==0){
		nr=nr+r;}
    }
g<<i;
if(nr!=p){g<<"-1";}
f.close();
g.close();
return 0;
}