#include<iostream>
#include<stdlib.h>
#include<cmath>
using namespace std;

unsigned long long q(int x)
{   unsigned long long a = x;
    unsigned long long mult = 1;
    while ( a >1)
     {
         mult *= a%10;
         a= a/10;
     }
     return mult*x;
}


int compare (const void * a, const void * b)
{
   if ( *(unsigned long long*)a <  *(unsigned long long*)b ) return -1;
  if ( *(unsigned long long*)a == *(unsigned long long*)b ) return 0;
  if ( *(unsigned long long*)a >  *(unsigned long long*)b ) return 1;
}

int main(){
  unsigned long long l ;
  unsigned long long k ;
  unsigned long long r;
  cin>>l>>k;
  unsigned long long x =1;
  unsigned long long n = 0;
  unsigned long long mas[l+10];
     for(unsigned long long i = 0 ; i < l+10 ; i++)
             mas[i] = pow(10 ,18);
  while (n < (l+10))
  {
      if(q(x) >= l ){
        mas[n] = q(x);
        //cout<< n << "   "  << x << "      " << q(x)<<endl;
        n++;
      }
       x++;
  }
  qsort(mas , l ,sizeof(unsigned long long),compare  );
  cout<<mas[k - 1 ];
return 0 ;
}