#include <iostream>
#include <vector>
#include <algorithm>
using namespace std;

bool isIntersect(int k1, int k2) {
    return k1!= k2;
}

int main() {
    int n;
    cin >> n;
    vector<vector<int>> roads(n, vector<int>(4));
 
    for (int i = 0; i < n; ++i) {
        for (int j = 0; j < 4; ++j) {
            cin >> roads[i][j];
        }
    }
    int maxCost = 0;
    for (int i = 0; i < n; ++i) {
        int costSum = 0;
        for (int j = 0; j < n; ++j) {
            if (i!= j) {
                int k1 = roads[i][2];
                int v2 = roads[j][3];
               
                if (isIntersect(k1, roads[j][2])) {
                    costSum += v2;
                }
            }
        }
    
        maxCost = max(maxCost, costSum);
    }
    cout << maxCost << endl;
    return 0;
}