#include <iostream>
using namespace std;

//ifstream fin("fact.in");
//ofstream fout("fact.out");

int main()
{
    int p,i,n;
    cin>>p;
    for(n=5;p>0;n+=5)
    {
        i=n;
        while(i%5==0)
        {
            p--;
            i/=5;
        }
    }
    if(n==5)
        cout<<1;
    else
        if(p==0)
            cout<<n-5;
            else
                cout<<-1;
}