#include <bits/stdc++.h>
using namespace std;
using ll = long long;

void add(string &a, ll x) {
	auto it = a.rbegin();
	while (x) {
		x = x + (*it - '0');
		*it = '0' + x%10;
		x /= 10;
		++it;
	}
}

string solve1(string n, string m) {
	if (n.find(m) != n.npos) return n;
	string a = n;
	ll p = 1;
	for (int i = 0; i < ssize(m); i++) a.rbegin()[i] = m.rbegin()[i], p *= 10;
	if (a < n) {
		add(a, p);
	}
	string b = n;
	for (int i = 0; i < ssize(m); i++) b.rbegin()[i+1] = m.rbegin()[i];
	b.back() = '0';
	if (n <= b && b < a) return b;
	return a;
}

string solve2(string n, string m) {
	ll lm = stoll(m);
	ll r = 0;
	for (char ch: n) {
		r = (r * 10 + ch - '0') % lm;
	}
	add(n, (lm-r)%lm);
	return n;
}

int main() {
	cin.tie(nullptr);
	ios_base::sync_with_stdio(false);
	int n_tests;
	cin >> n_tests;
	for (int test = 0; test < n_tests; test++) {
		string n, m;
		cin >> n >> m;
		n.insert(0, "00000000000");
		add(n, 1);
		//cerr << solve1(n, m) << " " << solve2(n, m) << "\n";
		cout << min(solve1(n, m), solve2(n, m)) << "\n";
	}
}