#include<atcoder/all>
#include<cstdio>
#include<vector>
#include<queue>
#include<map>
#include<set>
#include<unordered_map>
#include<stack>
#include<string>
#include<algorithm>
#include<functional>
#include<cstring>
#include<complex>
#include<bitset>
#include<iostream>
#include<cassert>
using namespace std;
using namespace atcoder;

typedef long long ll;
typedef unsigned long long ull;
typedef pair<ll, ll> P;
typedef pair<ll, P> Q;
typedef complex<double> C;
#define cx real()
#define cy imag()
const ll INF = 1LL << 60;
const double DINF = 1e30;
const ll mod = 1000000007;
const ll dx[4] = {1, 0, -1, 0};
const ll dy[4] = {0, -1, 0, 1};
const C I = C(0, 1);
const double EPS = 1e-10;
const ll NCK_MAX = 510000;

ll gcd(ll a, ll b) {
  if (b == 0) return a;
  return gcd(b, a % b);
}

ll *fac, *finv, *inv;

void nCk_init(ll mod) {
  fac = new ll[NCK_MAX];
  finv = new ll[NCK_MAX];
  inv = new ll[NCK_MAX];
  fac[0] = fac[1] = 1;
  finv[0] = finv[1] = 1;
  inv[1] = 1;
  for (ll i = 2; i < NCK_MAX; i++) {
    fac[i] = fac[i-1] * i % mod;
    inv[i] = mod - inv[mod%i] * (mod / i) % mod;
    finv[i] = finv[i-1] * inv[i] % mod;
  }
}

ll nCk(ll n, ll k, ll mod) {
  if (fac == NULL) nCk_init(mod);
  if (n < k) return 0;
  if (n < 0 || k < 0) return 0;
  return fac[n] * (finv[k] * finv[n-k] % mod) % mod;
}

template <typename T>
class Zip {
  vector<T> d;
  bool flag;
  void init() {
    sort(d.begin(), d.end());
    d.erase(unique(d.begin(), d.end()), d.end());
    flag = false;
  }
public:
  Zip() {
    flag = false;
  }
  void add(T x) {
    d.push_back(x);
    flag = true;
  }
  ll getNum(T x) {
    if (flag) init();
    return lower_bound(d.begin(), d.end(), x) - d.begin();
  }
  ll size() {
    if (flag) init();
    return (ll)d.size();
  }
};

class UnionFind {
  vector<ll> par, rank; // par > 0: number, par < 0: -par
public:
  UnionFind(ll n) : par(n, 1), rank(n, 0) {}
  ll getSize(ll x) {
    return par[find(x)];
  }
  ll find(ll x) {
    if (par[x] > 0) return x;
    return -(par[x] = -find(-par[x]));
  }
  void merge(ll x, ll y) {
    x = find(x);
    y = find(y);
    if (x == y) return;
    if (rank[x] < rank[y]) {
      par[y] += par[x];
      par[x] = -y;
    } else {
      par[x] += par[y];
      par[y] = -x;
      if (rank[x] == rank[y]) rank[x]++;
    }
  }
  bool isSame(ll x, ll y) {
    return find(x) == find(y);
  }
};


template <typename T>
class SegmentTree {
  ll n;
  vector<T> node;
  function<T(T, T)> fun, fun2;
  bool customChange;
  T outValue, initValue;
public:
  void init(ll num, function<T(T, T)> resultFunction, T init, T out, function<T(T, T)> changeFunction = NULL) {
    // changeFunction: (input, beforevalue) => newvalue
    fun = resultFunction;
    fun2 = changeFunction;
    customChange = changeFunction != NULL;
    n = 1;
    while (n < num) n *= 2;
    node.resize(2 * n - 1);
    fill(node.begin(), node.end(), init);
    outValue = out;
    initValue = init;
  }
  void valueChange(ll num, T value) {
    num += n-1;
    if (customChange) node[num] = fun2(value, node[num]);
    else node[num] = value;
    while (num > 0) num = (num - 1) / 2, node[num] = fun(node[num * 2 + 1], node[num * 2 + 2]);
  }
  T rangeQuery(ll a, ll b, ll l = 0, ll r = -1, ll k = 0) { // [a, b)
    if (r == -1) r = n;
    if (a <= l && r <= b) return node[k];
    if (b <= l || r <= a) return outValue;
    ll mid = (l + r) / 2;
    return fun(rangeQuery(a, b, l, mid, 2*k+1), rangeQuery(a, b, mid, r, 2*k+2));
  }
};

template <typename T>
class Graph {
  struct edge { ll to; T cost; };
  struct edge_data { ll from, to; T cost; };

  ll v;
  vector<vector<edge>> e, re;
  vector<edge_data> ed;
  vector<bool> used;
  vector<ll> vs, cmp;
  bool isDirected, isMinasEdge;
public:
  Graph(ll _v, bool _isDirected = true, ll range_add = 0) {
    // range_add 0:no / 1:in / 2:out / 3:in+out
    //_v++;
    v = _v, isDirected = _isDirected; isMinasEdge = false;
    e.resize(v), re.resize(v);
  }
  void add_edge(ll s, ll t, T cost = 1) {
    e[s].push_back((edge){t, cost});
    if (!isDirected) e[t].push_back((edge){s, cost});
    else re[t].push_back((edge){s, cost});
    ed.push_back((edge_data){s, t, cost});
    if (cost < 0) isMinasEdge = true;
  }
  vector<T> dijkstra(ll s) {
    vector<T> d(v, INF);
    d[s] = 0;
    auto edge_cmp = [](const edge& a, const edge& b) { return a.cost > b.cost; };
    priority_queue<edge, vector<edge>, decltype(edge_cmp)> pq(edge_cmp);
    pq.push((edge){s, 0});
    while (!pq.empty()) {
      edge temp = pq.top(); pq.pop();
      if (d[temp.to] < temp.cost) continue;
      for (const edge& next : e[temp.to]) {
        T cost = temp.cost + next.cost;
        if (d[next.to] > cost) {
          d[next.to] = cost;
          pq.push((edge){next.to, cost});
        }
      }
    }
    return d;
  }
  vector<T> bellmanford(ll s) {
    vector<T> d(v, INF);
    d[s] = 0;
    for (ll i = 0; i < v; i++) {
      for (const edge_data& temp : ed) {
        if (d[temp.from] != INF && d[temp.to] > d[temp.from] + temp.cost) d[temp.to] = d[temp.from] + temp.cost;
        if (!isDirected && d[temp.to] != INF && d[temp.from] > d[temp.to] + temp.cost) d[temp.from] = d[temp.to] + temp.cost;
      }
    }
    for (ll i = 0; i < v; i++) {
      for (const edge_data& temp : ed) {
        if (d[temp.from] != INF && d[temp.to] > d[temp.from] + temp.cost) d[temp.to] = -INF;
        if (!isDirected && d[temp.to] != INF && d[temp.from] > d[temp.to] + temp.cost) d[temp.from] = -INF;
      }
    }
    return d;
  }
  vector<T> shortest_path(ll s) {
    if (isMinasEdge) return bellmanford(s);
    else return dijkstra(s);
  }
  T kruskal() {
    // if (isDirected)
    UnionFind uf(v);
    auto edge_data_cmp = [](const edge_data& a, const edge_data& b) { return a.cost < b.cost; };
    sort(ed.begin(), ed.end(), edge_data_cmp);
    T ans = 0;
    for (const edge_data& temp : ed) {
      if (uf.isSame(temp.from, temp.to)) continue;
      uf.merge(temp.from, temp.to);
      ans += temp.cost;
    }
    return ans;
  }
  void scc_dfs(ll s) {
    used[s] = true;
    for (const edge& i : e[s]) if (!used[i.to]) scc_dfs(i.to);
    vs.push_back(s);
  }
  void scc_rdfs(ll s, ll k) {
    used[s] = true;
    cmp[s] = k;
    for (const edge& i : re[s]) if (!used[i.to]) scc_rdfs(i.to, k);
  }
  vector<ll> scc() {
    used.resize(v);
    fill(used.begin(), used.end(), false);
    cmp.resize(v);
    vs.clear();
    for (ll i = 0; i < v; i++) if (!used[i]) scc_dfs(i);
    used.resize(v);
    fill(used.begin(), used.end(), false);
    ll k = 0;
    for (ll i = vs.size() - 1; i >= 0; i--) if (!used[vs[i]]) scc_rdfs(vs[i], k++);
    return cmp;
  }
};

class RollingHash {
  int base;
  vector<__int128> hash;
  vector<__int128> pw;
  const __int128 hashmod = (1ull << 61) - 1;
public:
  RollingHash(string s, int base = 10007) : base(base), hash(s.length()+1, 0), pw(s.length()+1, 1) {
    for (int i = 0; i < (int)s.length(); i++) {
      hash[i+1] = (hash[i] * base + s[i]) % hashmod;
      pw[i+1] = pw[i] * base % hashmod;
    }
  }
  ll get(ll a, ll b) { // [a, b)
    __int128 tmp = hashmod + hash[b] - hash[a] * pw[b-a] % hashmod;
    if (tmp >= hashmod) tmp -= hashmod;
    return (ll)tmp;
  }
};

ll t, n, m, a, b;

__int128 g(ll i, ll a, ll m) {
  __int128 x = m/a, y = (m-1)%a, mul = (x+1) * (y+1);
  __int128 ans = 0;
  __int128 l = y * (y+1) * (x+1) / 2;
  __int128 r = (a-1-y) * (y+1+a-1) * x / 2;
  if (i >= m) {
    __int128 tmp = i/m;
    ans += (l + r) * tmp;
    if (tmp >= 1) ans += a * m * (tmp-1) * tmp / 2;
    ans += a * tmp * (i%m);
    i %= m;
  }
  if (i < mul) {
    __int128 num = i / (x+1), rest = i % (x+1);
    ans += num*(num-1)*(x+1)/2;
    ans += num * rest;
  } else {
    ans += l;
    __int128 num = (i-mul) / x + y, rest = (i-mul) % x;
    ans += ((num+y+1)*(num-y))*x/2;
    ans += num * rest;
  }
  printf("g=%lld\n", (ll)ans);
  return ans;
}

__int128 f(ll i, ll a, ll m) {
  __int128 ans = (__int128)a * i * (i-1) / 2 - g(i, a, m) * m;
  cout << "f=" << (ll)ans << endl;
  return ans;
}

int main() {
  scanf("%lld", &t);
  for (ll i = 0; i < t; i++) {
    scanf("%lld%lld%lld%lld", &n, &m, &a, &b);
    printf("%lld\n", floor_sum(n, m, a, b));
    /*
    ll g = gcd(a, m);
    a /= g;
    b /= g;
    m /= g;
    printf("a%lld b%lld m%lld\n", a, b, m);
    if (a == 0) {
      printf("%lld\n", (b/m) * n);
    } else {
      ll k = b * inv_mod(a, m) % m;
      printf("%lld!%lld!!\n", (a * k % m), b);
      __int128 ans = ((((__int128)a * (n-1) + 2*b) * n / 2) - ((f(n+k, a, m) - f(k, a, m)))) / m;
      printf("%lld\n", (ll)ans);
    }
    */
  }
}


Measured memory_bytes: 3792