#include<bits/stdc++.h>
using namespace std;
#define int long long
#define endl '\n'

void QAQ() {
    int k;
    string x;
    cin >> x >> k;

    reverse(x.begin(), x.end());
    int n = x.size();

    vector<int> a(n + 2 + k);

    for (int i = 1; i <= n; i++) {
        a[i] = x[i - 1] - '0';
    }

    vector dp(min(n + 2 + k, (int)25), vector(k + 1, vector<__int128>(2, 4e18)));
    dp[0][0][0] = 0;

    __int128 tmp = 1;

    for (int i = 1; i <= min(n + k + 1, (int)24); i++) {
        for (int j = 0; j <= k; j++) {
            if (a[i] + 1 < 10) {
                dp[i][j][0] = min(dp[i][j][0], dp[i - 1][j][1]);
            }
            dp[i][j][0] = min(dp[i][j][0], dp[i - 1][j][0]);
            if (j >= 1) {
                dp[i][j][1] = min(dp[i][j][1], dp[i - 1][j - 1][1] + tmp * (9 - a[i]));
                dp[i][j][1] = min(dp[i][j][1], dp[i - 1][j - 1][0] + tmp * (10 - a[i]));
            }
        }
        tmp *= 10;
    }

    int ans = min(dp[min(n + k + 1, (int)24)][k][0], dp[min(n + k + 1, (int)24)][k][1]);

    if (ans == 0) {
        tmp = 1;
        for (int i = 1; i <= min(n + k + 1, (int)24); i++) {
            if (a[i] + 1 < 10) {
                cout << (int)tmp << "\n";
                return;
            }
            tmp *= 10;
        }
    } else if (ans == 4e18) {
        cout << "-1\n";
    } else {
        cout << ans << "\n";
    }
}

signed main() {
    cin.tie(0) -> sync_with_stdio(0);
    int t = 1;
    cin >> t;

    while (t--) {
        QAQ();
    }
}