#include <iostream>

using namespace std;

int baza(int n, int b)
{
    int x = 0, p = 1, r;
    while(n)
    {
        r=n%b;
        x= x + r*p;
        p*=10;
        n/=b;
    }
    return x;
}

int cmax(int n)
{
    int maxim = 0;
    while(n)
    {
        if(n%10>maxim)
        {
            maxim = n%10;
        }
        n/=10;
    }
    return maxim;
}

int main()
{
    int n, k;

    cin >> n >> k;

    cout << cmax(baza(n, k));

    return 0;

}