#include <bits/stdc++.h>   using namespace std;   const long long linf = 1e18 + 9;   const int inf = 1e9 + 9;   const int N = 1e3 + 9;   int n, m, c[N], d[N], a[N], b[N], dp[N][N], ans;   int main() {     cin >> n >> m >> c[0] >> d[0];     for (int i = 1; i <= m; i++) cin >> a[i] >> b[i] >> c[i] >> d[i];     for (int i = 1; i <= n; i++) {       for (int j = 1; j <= m; j++) {         int mx = -inf;         for (int k = 0; k <= a[j] / b[j]; k++) {           if (i - c[j] * k < 0) continue;           mx = max(mx, dp[i - c[j] * k][j - 1] + d[j] * k);         }         dp[i][j] = mx;       }     }     for (int i = 0; i <= n; i++) ans = max(ans, dp[i][m] + (n - i) / c[0] * d[0]);     cout << ans << endl;     return 0;   }   