#include <bits/stdc++.h>   using namespace std;   const int mod = 1000003;   long double pi = 3.1415926536;   const int mx = 1000003;   long long gcd(long long x, long long y) {     if (y == 0) return x;     return gcd(y, x % y);   }   long long bp(long long a, long long b) {     long long ans = 1;     while (b > 0) {       if (b & 1) ans = (ans * a) % mod;       a = (a * a) % mod;       b >>= 1;     }     return ans;   }   long long p(long long n) {     for (long long i = 2; i * i <= n; i++) {       if (n % i == 0) {         return n / i;       }     }     return 1;   }   void solve() {     long long a, d, x, i = 1;     cin >> a >> d;     x = a++;     while ((a % i) <= d) {       x = (a - (a % i));       i *= 10;     }     cout << x - 1;   }   int main() {     ios::sync_with_stdio(0);     cin.tie(0);     cout.tie(0);     solve();   }   