#include<fstream>

using namespace std;

long long int p,n,k,ok,x;
int main()
{
    ifstream fin("fact.in");
    ofstream fout("fact.out");
    fin>>p;
    if(p==0)
      fout<<1;
      else {
           for(n=4*p;n<=5*p;n++)
              {
              k=0;
              x=n;
              while(x)
                   {
                   k+=x/5;
                   x/=5;
                   }
              if(k==p)
                {
                fout<<n;
                n=5*p+1;
                ok=1;
                }
              }
           if(ok==0)
              fout<<-1;
           }
}