#include <bits/stdc++.h>   using namespace std;   int main() {     int n, m;     cin >> n >> m;     long long ans = 0;     for (int i = (0); i < (n); ++i) {       long long t, T, x, cost;       cin >> t >> T >> x >> cost;       if (t >= T) {         ans += cost + m * x;         continue;       }       long long aux1 = cost;       if (m > (T - t)) aux1 += m * x;       long long aux2 = (long long)ceil((double)(m - (T - t)) / (T - t)) + 1;       aux2 *= cost;       ans += min(aux1, aux2);     }     cout << ans << endl;     return 0;   }   