#include <bits/stdc++.h>
using namespace std;
int cnt_9s(long long int num);
long long int power(int num, int exp);
int main() {
  long long int num, sale, rem;
  cin >> num >> sale;
  while (1) {
    rem = power(10, cnt_9s(num) + 1);
    if (sale >= num % rem + 1)
      sale -= (num % rem + 1), num -= (num % rem + 1);
    else
      break;
  }
  cout << num << endl;
  return 0;
}
long long int power(int num, int exp) {
  long long int res = 1;
  while (exp != 0) res *= num, exp--;
  return res;
}
int cnt_9s(long long int num) {
  int cnt = 0;
  while (num != 0)
    if (num % 10 == 9)
      cnt++, num /= 10;
    else
      break;
  return cnt;
}
