#include<iostream>
#include<algorithm>
using namespace std;

using ll = long long;

ll count(ll x){
    if(x < 0) return 0;
    if(x == 0) return 1;
    ll ans = 1, b = 1;
    while(b <= x){
        ll u = x % b, h = x / (b * 10);
        ll cur = (x / b) % 10;
        if(cur == 0) ans += (h - 1) * b + u + 1;
		else ans += h * b;
        b *= 10;
    }
    return ans;
}

ll n, k;

int main(){
	freopen("whz_number.in", "r", stdin);
	freopen("whz_number.out", "w", stdout);
	cin.tie(0); ios::sync_with_stdio(0);
    while(cin >> n >> k){
        ll tot = count(n);
        ll tag = tot - k;
        ll l = 0, r = n, ans = -1;
        while(l <= r){
            ll mid = (l + r) / 2;
            if(count(mid) <= tag) ans = mid, l = mid + 1;
			else r = mid - 1;
        }
        cout << ans + 1 << '\n';
    }
    return 0;
}