#include <fstream>
#include <iomanip>
#include <string>

using namespace std;

long zero(long nr){
   long z=0,f=5;
   while (f<=nr){z+=nr/f; f*=5;}
   return z;   
}    
fstream fin("fact.in",ios::in),fout("fact.out",ios::out);
int z,n;

int main(){
    fin>>z; n=4*z; n-=n%5;
    if (z==0) fout<<1;
    else{
        while (zero(n)<z) n+=5;
        if (z==zero(n)) fout<<n; else fout<<-1;
    }    
fin.close();fout.close();
}