/**
 * code generated by JHelper
 * More info: https://github.com/AlexeyDmitriev/JHelper
 * @author Pine1999
 */

#include <bits/stdc++.h>
//#include "../library/dsu.hpp"
//#include "../library/fenwicktree.hpp"
//#include "../library/modint.hpp"
//#include "../library/segtree.hpp"
//#include "../library/string.hpp"
#ifndef ATCODER_MATH_HPP
#define ATCODER_MATH_HPP 1

#include <algorithm>
#include <cassert>
#include <tuple>
#include <vector>
#ifndef ATCODER_INTERNAL_MATH_HPP
#define ATCODER_INTERNAL_MATH_HPP 1

#include <utility>

namespace atcoder {

    namespace internal {

// @param m `1 <= m`
// @return x mod m
        constexpr long long safe_mod(long long x, long long m) {
            x %= m;
            if (x < 0) x += m;
            return x;
        }

// Fast moduler by barrett reduction
// Reference: https://en.wikipedia.org/wiki/Barrett_reduction
// NOTE: reconsider after Ice Lake
        struct barrett {
            unsigned int _m;
            unsigned long long im;

            // @param m `1 <= m`
            barrett(unsigned int m) : _m(m), im((unsigned long long)(-1) / m + 1) {}

            // @return m
            unsigned int umod() const { return _m; }

            // @param a `0 <= a < m`
            // @param b `0 <= b < m`
            // @return `a * b % m`
            unsigned int mul(unsigned int a, unsigned int b) const {
                // [1] m = 1
                // a = b = im = 0, so okay

                // [2] m >= 2
                // im = ceil(2^64 / m)
                // -> im * m = 2^64 + r (0 <= r < m)
                // let z = a*b = c*m + d (0 <= c, d < m)
                // a*b * im = (c*m + d) * im = c*(im*m) + d*im = c*2^64 + c*r + d*im
                // c*r + d*im < m * m + m * im < m * m + 2^64 + m <= 2^64 + m * (m + 1) < 2^64 * 2
                // ((ab * im) >> 64) == c or c + 1
                unsigned long long z = a;
                z *= b;
#ifdef _MSC_VER
                unsigned long long x;
        _umul128(z, im, &x);
#else
                unsigned long long x =
                        (unsigned long long)(((unsigned __int128)(z)*im) >> 64);
#endif
                unsigned int v = (unsigned int)(z - x * _m);
                if (_m <= v) v += _m;
                return v;
            }
        };

// @param n `0 <= n`
// @param m `1 <= m`
// @return `(x ** n) % m`
        constexpr long long pow_mod_constexpr(long long x, long long n, int m) {
            if (m == 1) return 0;
            unsigned int _m = (unsigned int)(m);
            unsigned long long r = 1;
            unsigned long long y = safe_mod(x, m);
            while (n) {
                if (n & 1) r = (r * y) % _m;
                y = (y * y) % _m;
                n >>= 1;
            }
            return r;
        }

// Reference:
// M. Forisek and J. Jancina,
// Fast Primality Testing for Integers That Fit into a Machine Word
// @param n `0 <= n`
        constexpr bool is_prime_constexpr(int n) {
            if (n <= 1) return false;
            if (n == 2 || n == 7 || n == 61) return true;
            if (n % 2 == 0) return false;
            long long d = n - 1;
            while (d % 2 == 0) d /= 2;
            for (long long a : {2, 7, 61}) {
                long long t = d;
                long long y = pow_mod_constexpr(a, t, n);
                while (t != n - 1 && y != 1 && y != n - 1) {
                    y = y * y % n;
                    t <<= 1;
                }
                if (y != n - 1 && t % 2 == 0) {
                    return false;
                }
            }
            return true;
        }
        template <int n> constexpr bool is_prime = is_prime_constexpr(n);

// @param b `1 <= b`
// @return pair(g, x) s.t. g = gcd(a, b), xa = g (mod b), 0 <= x < b/g
        constexpr std::pair<long long, long long> inv_gcd(long long a, long long b) {
            a = safe_mod(a, b);
            if (a == 0) return {b, 0};

            // Contracts:
            // [1] s - m0 * a = 0 (mod b)
            // [2] t - m1 * a = 0 (mod b)
            // [3] s * |m1| + t * |m0| <= b
            long long s = b, t = a;
            long long m0 = 0, m1 = 1;

            while (t) {
                long long u = s / t;
                s -= t * u;
                m0 -= m1 * u;  // |m1 * u| <= |m1| * s <= b

                // [3]:
                // (s - t * u) * |m1| + t * |m0 - m1 * u|
                // <= s * |m1| - t * u * |m1| + t * (|m0| + |m1| * u)
                // = s * |m1| + t * |m0| <= b

                auto tmp = s;
                s = t;
                t = tmp;
                tmp = m0;
                m0 = m1;
                m1 = tmp;
            }
            // by [3]: |m0| <= b/g
            // by g != b: |m0| < b/g
            if (m0 < 0) m0 += b / s;
            return {s, m0};
        }

// Compile time primitive root
// @param m must be prime
// @return primitive root (and minimum in now)
        constexpr int primitive_root_constexpr(int m) {
            if (m == 2) return 1;
            if (m == 167772161) return 3;
            if (m == 469762049) return 3;
            if (m == 754974721) return 11;
            if (m == 998244353) return 3;
            int divs[20] = {};
            divs[0] = 2;
            int cnt = 1;
            int x = (m - 1) / 2;
            while (x % 2 == 0) x /= 2;
            for (int i = 3; (long long)(i)*i <= x; i += 2) {
                if (x % i == 0) {
                    divs[cnt++] = i;
                    while (x % i == 0) {
                        x /= i;
                    }
                }
            }
            if (x > 1) {
                divs[cnt++] = x;
            }
            for (int g = 2;; g++) {
                bool ok = true;
                for (int i = 0; i < cnt; i++) {
                    if (pow_mod_constexpr(g, (m - 1) / divs[i], m) == 1) {
                        ok = false;
                        break;
                    }
                }
                if (ok) return g;
            }
        }
        template <int m> constexpr int primitive_root = primitive_root_constexpr(m);

    }  // namespace internal

}  // namespace atcoder

#endif  // ATCODER_INTERNAL_MATH_HPP


namespace atcoder {

    long long pow_mod(long long x, long long n, int m) {
        assert(0 <= n && 1 <= m);
        if (m == 1) return 0;
        internal::barrett bt((unsigned int)(m));
        unsigned int r = 1, y = (unsigned int)(internal::safe_mod(x, m));
        while (n) {
            if (n & 1) r = bt.mul(r, y);
            y = bt.mul(y, y);
            n >>= 1;
        }
        return r;
    }

    long long inv_mod(long long x, long long m) {
        assert(1 <= m);
        auto z = internal::inv_gcd(x, m);
        assert(z.first == 1);
        return z.second;
    }

// (rem, mod)
    std::pair<long long, long long> crt(const std::vector<long long>& r,
                                        const std::vector<long long>& m) {
        assert(r.size() == m.size());
        int n = int(r.size());
        // Contracts: 0 <= r0 < m0
        long long r0 = 0, m0 = 1;
        for (int i = 0; i < n; i++) {
            assert(1 <= m[i]);
            long long r1 = internal::safe_mod(r[i], m[i]), m1 = m[i];
            if (m0 < m1) {
                std::swap(r0, r1);
                std::swap(m0, m1);
            }
            if (m0 % m1 == 0) {
                if (r0 % m1 != r1) return {0, 0};
                continue;
            }
            // assume: m0 > m1, lcm(m0, m1) >= 2 * max(m0, m1)

            // (r0, m0), (r1, m1) -> (r2, m2 = lcm(m0, m1));
            // r2 % m0 = r0
            // r2 % m1 = r1
            // -> (r0 + x*m0) % m1 = r1
            // -> x*u0*g % (u1*g) = (r1 - r0) (u0*g = m0, u1*g = m1)
            // -> x = (r1 - r0) / g * inv(u0) (mod u1)

            // im = inv(u0) (mod u1) (0 <= im < u1)
            long long g, im;
            std::tie(g, im) = internal::inv_gcd(m0, m1);

            long long u1 = (m1 / g);
            // |r1 - r0| < (m0 + m1) <= lcm(m0, m1)
            if ((r1 - r0) % g) return {0, 0};

            // u1 * u1 <= m1 * m1 / g / g <= m0 * m1 / g = lcm(m0, m1)
            long long x = (r1 - r0) / g % u1 * im % u1;

            // |r0| + |m0 * x|
            // < m0 + m0 * (u1 - 1)
            // = m0 + m0 * m1 / g - m0
            // = lcm(m0, m1)
            r0 += x * m0;
            m0 *= u1;  // -> lcm(m0, m1)
            if (r0 < 0) r0 += m0;
        }
        return {r0, m0};
    }

    long long floor_sum(long long n, long long m, long long a, long long b) {
        long long ans = 0;
        if (a >= m) {
            ans += (n - 1) * n * (a / m) / 2;
            a %= m;
        }
        if (b >= m) {
            ans += n * (b / m);
            b %= m;
        }

        long long y_max = (a * n + b) / m, x_max = (y_max * m - b);
        if (y_max == 0) return ans;
        ans += (n - (x_max + a - 1) / a) * y_max;
        ans += floor_sum(y_max, a, m, (a - x_max % a) % a);
        return ans;
    }

}  // namespace atcoder

#endif  // ATCODER_MATH_HPP


using namespace std;
using namespace atcoder;

#define ll long long
#define rep(i, n) for (int i = 0; i < (int) n; ++i)

template<class T> bool uin(T &a, T b) { return a > b ? (a = b, true) : false; }
template<class T> bool uax(T &a, T b) { return a < b ? (a = b, true) : false; }

void CFloorSum(std::istream& in, std::ostream& out) {
    int t;
    in >> t;
    while (t--) {
        ll n, m, a, b;
        in >> n >> m >> a >> b;
        out << floor_sum(n, m, a, b) << '\n';
    }
}

int main() {
    ios::sync_with_stdio(false);
    cin.tie(nullptr);
    std::istream& in(std::cin);
    std::ostream& out(std::cout);
    CFloorSum(in, out);
    return 0;
}

Measured memory_bytes: 3676