#include<cstdio>
#define InFile "fact.in"
#define OutFile "fact.out"
using namespace std;
long long p;
unsigned long long nr;
unsigned short v[3000],i;
int main()
{
     FILE *f=fopen(InFile,"r");
     FILE *g=fopen(OutFile,"w");
    fscanf(f,"%lld",&p);
     if (p==0){ fprintf(g,"1");return 0;}

    while(p>0)
   {
     nr+=5;++v[1];i=1;--p;
      while(v[i])
       if(v[i]==5){v[i]=0;v[++i]++;--p;}else break;

    }

    if(p<0)fprintf(g,"-1");
      else fprintf(g,"%lld",nr);
    return 0;
}