#include <bits/stdc++.h>

using namespace std;

ifstream in("fact.in");
ofstream out("fact.out");


int main()
{
    int P;

    in>>P;

    if(P == 0)
    {
        out<<1;
        return 0;
    }

    int nz=0;

    for(int i = 1; i <= 100000000/2 + 1; ++i)
    {
        int j = i;
        int c = 0;
        while(j % 5 == 0)
        {
            ++c;
            j /= 5;
        }
        nz += (c + 1);
        //cout<<i*5<<" "<<nz<<"\n";
        if(nz == P)
        {
            out<<i*5;
            return 0;
        }
        else if(nz > P)
        {
            out<<-1<<"\n";
            return 0;
        }
    }

    return 0;
}