#include <iostream>
#include <fstream>
using namespace std;
int main()
{
    ifstream fin("fact.in");
    ofstream fout("fact.out");
    unsigned long long p,d2=0,d5=0,d10=0,i,t;
    fin>>p;
    if(p==0){fout<<1;return 0;}
    for(i=1;i;i++)
    {
        t=i;
        while(t%2==0)d2++,t/=2;
        t=i;
        while(t%5==0)d5++,t/=5;
        if(min(d2,d5)==p)
        {
            fout<<i;return 0;
        }
        if(min(d2,d5)>p)
        {
            fout<<-1;return 0;
        }

    }
}