#include<iostream>
#include<stdio.h>
using namespace std;

FILE*f=fopen("fact.in","r");
FILE*g=fopen("fact.out","w");

int p,k,i,j,nr,ok;

int main()
{
    fscanf(f,"%d",&p);

    k=1;
    while(k<p) k=k*5;

    ok=0;
    for(i=k;i<=k*5-1;i=i+5) {
      nr=0;
      for(j=5;j<=k;j=j*5) {
        nr=nr+i/j;
      }
      if(nr==p) {ok=1; break;}
    }

    if(ok==0) fprintf(g,"%d",-1);
    else fprintf(g,"%d",i);

    return 0;
}