#include <iostream>
#include <cmath>
#include <algorithm>
#include <math.h>
#include <vector>
#include <fstream>

using namespace std;

int getSize(int x) {
    int l = 0;
    while (x > 0) {
        l++;
        x /= 10;
    }

    return l;
}

int countAmount(long long N, long long x) {

    int l = getSize(x);
    int p = pow(10, l);
    if (p % 10 != 0) p++;

    int myAns = 0;
    myAns = N/p;
    if ( N % p > x)  {
        myAns++;
    }

    return myAns;
}

int main()
{

    long long k = 0;
    long long M, N;
    cin >> M >> N;

    int t = pow(10, N);
    if (t % 10 != 0) t++;

    int d = pow(2, N);
    if (d % 2 != 0) d--;

    //cout << d << endl;
    long long ans = 0;

    for (int i = d; i < t; i+=d) {
            ans += countAmount(M, i);
            //cout << "i " << i << " ans " << ans << endl;
        }

    cout << ans;

    return 0;
}