#include<fstream>
#include<math.h>
using namespace std;
int main()
{
    ifstream f("fact.in");
    ofstream g("fact.out");
    
    long p,x,zero=0;
    int i;
    bool ok=true;
    f>>p;
    f.close();
    if(p==0)g<<"1\n";
    else
    
    for(i=5;i<=900000000;i+=5)
    {
            x=i;
            while(x%5==0)
              {zero++;x/=5;}            
          if(zero>=p) {g<<i<<"\n"; break;ok=true;}
          
                 
    }
    if(!ok)
    g<<-1;
  
    
    
return 0;    
}