using namespace std;
#include<fstream>

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




int main()
{

    int p,i,n=0,i2;


    f>>p;

    if(!p) g<<1;
    else
    {
        for(i=5; n<p; i+=5)
        {
            i2=i;
            while(i2%5==0)
            {
                i2/=5;
                n++;
            }
        }
        if(n==p) g<<i-5;
        else g<<-1;
    }


    return 0;
}