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

#define int long long
using i128 = __int128_t;

i128 make_num(int digit, int len) {
    i128 num = 0;
    for (int i = 0; i < len; i++) {
        num = num * 10 + digit;
    }
    return num;
}

i128 abs128(i128 x) {
    return (x < 0 ? -x : x);
}

signed main() {
    ios::sync_with_stdio(false);
    cin.tie(nullptr);

    int h;
    cin >> h;

    while (h--) {
        int f, t;
        cin >> f >> t;

        vector<int> v(2);
        cin >> v[0] >> v[1];

        int a = v[0];
        int b = v[1];

        int n = 0;
        int s = f;

        if (s == 0) n = 1;
        while (s > 0) {
            s /= 10;
            n++;
        }

        i128 x = make_num(a, n);
        i128 y = make_num(b, n);

        i128 z = a;
        for (int i = 1; i < n; i++)
            z = z * 10 + b;

        i128 p = b;
        for (int i = 1; i < n; i++)
            p = p * 10 + a;

        i128 q = make_num(b, max(0LL, n - 1));
        i128 r = make_num(a, n + 1);

        i128 F = f;

        i128 ans = min({
            abs128(F - x),
            abs128(F - y),
            abs128(F - z),
            abs128(F - p),
            abs128(F - q),
            abs128(F - r)
        });

        cout << (long long)ans << '\n';
    }

    return 0;
}