#include<fstream>
#include<iostream>
using namespace std;
int main()
{
 int p,n=0;
 ifstream fin("fact.in");
 fin>>p;
 fin.close();
 ofstream fout("fact.out");
 if(p==0)n=1;
 while(p)
 {
 	n+=5;
 	p--;
 	if(n/25<5)p-=2;
    if(n/125<5)p-=3;
    if(n/625<5)p-=4;
    if(n/3125<5)p-=5;
    if(n/15625<5)p-=6;
 	if(n/78125<5)p-=7;
 	if(n/390625<5)p-=8;
 	if(n/1953125<5)p-=9;
 	if(n/9765625<5)p-=10;
 	if(n/48828125<5)p-=11;
 	if(n/244140625<5)p-=12;
 	if(n/1220703125<5)p-=13;
 }
 if(p<0)n=-1;   
 fout<<n;
 fout.close();
 return 0;
}