#include <cstdio>

int nrfact(int x)
{
    int n2=0,n5=0;
    for(int i=1;i<=x;i++)
        {if(i%2==0)
        {
            int aux=i;
         while(aux%2==0)
          n2++,aux/=2;
        }
         if(i%5==0)
        {
            int aux=i;
         while(aux%5==0)
          n5++,aux/=5;
        }
        }
    if(n2<n5)
        return n2;
    return n5;
}

int main()
{
    freopen("fact.in","r",stdin);
    freopen("fact.out","w",stdout);
  int x;
  scanf("%d",&x);
  int li=1,lf=100000000;
  int mj;
  while(st<=dr)
  {
      mj=(li+lj)/2;
      if(x<=nrfact(a[mj]))
        lf=mj-1;
      else
        li=mj+1;
  }
  if(li>n || nrfact(a[li])!=x)
        return -1;
  else
    printf("%d",a[mj])
    return 0;
}