#include <bits/stdc++.h>

using namespace std;
ifstream in("gfact.in");
ofstream out("gfact.out");
int INF=5e8;
int nr0(int n,int q)
{
    int s=0;
  int p=q;
    while(n>=p)
    {
        s=s+n/p;
        p*=q;
    }
    return s;
}
int main()
{
   int x,y;
   in>>x>>y;
  int st=1;
  int dr=INF;
  int rez=-1;
   while(st<=dr)
   {
       int m=(st+dr)/2;
       if(nr0(m,x)==y)
       {
           rez=m;
           dr=m-1;
       }
       else if(nr0(m,x)<y)
       {
           st=m+1;
       }
       else{
        dr=m-1;
       }

   }
   out<<rez;
    return 0;
}