#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;
    int s=f;
    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, 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;
    }
    
}