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

ll floor_div(ll num, ll div){
    if(div < 0){
        div = -div;
        num = -num;
    }
    if(num >= 0) return num / div;
    return (num - (div - 1)) / div;
}

int main(){
    ios::sync_with_stdio(false);
    cin.tie(0);
    int T;
    cin >> T;
    while(T--){
        ll n, m, a, b, c, d;
        cin >> n >> m >> a >> b >> c >> d;
        auto rec = [&](auto rec, ll n, ll m, ll a, ll b, ll c, ll d) -> ll {
            ll ofs = 0;
            
            auto f = [&](ll x){ return a * x + b * floor_div(c * x + d, m); };

            assert(c >= 0 && d >= 0);
            ll dc = c / m, dd = d / m;
            a += b * dc;
            c -= dc * m;
            ofs += b * dd;
            d -= dd * m;

            if((a >= 0) ^ (b >= 0) ^ true) return ofs + max(f(0), f(n - 1));

            // floor((C(N-1) + D) / M) の最大値
            ll num = (c * (n - 1) + d) / m;
            if(num == 0) return ofs + max(f(0), f(n - 1));

            ll res = ofs;
            if(a < 0){
                res = max(res, ofs + b + rec(rec, num, c, b, a, m, m + c - 1 - d));
            }else{
                res += a * (n - 1) + b * num;
                res = max(res, ofs + rec(rec, num, c, b, a, m, m - d - 1));
            }
            return res;
        };

        cout << rec(rec, n, m, a, b, c, d) << '\n';
    }
}