#include <bits/stdc++.h>
using namespace std;
const int N = 2010, M = 10010;
int n, m, p[N];

struct Edge {
    int a, b, c;
    bool operator<(const Edge &t) const {
        return c < t.c;
    }
} edge[M];
int el;

int find(int x) {
    if (p[x] != x) p[x] = find(p[x]);
    return p[x];
}

int res;

int main() {
    cin >> n >> m;

    // 初始化并查集
    for (int i = 1; i <= n; i++) p[i] = i;

    for (int i = 0; i < m; i++) {
        int a, b, c, t;
        cin >> t >> a >> b >> c;
        if (t == 1) // 必选的加入到同一个并查集
            p[find(a)] = find(b), res += c;
        else
            // 记录可选边有哪些
            edge[el++] = {a, b, c};
    }
    // 对可选边进行由小到大排序
    sort(edge, edge + el);

    // 枚举每条可选边
    for (int i = 0; i < el; i++) {
        int a = find(edge[i].a), b = find(edge[i].b), c = edge[i].c;
        if (a != b) p[a] = b, res += c;
    }

    // 输出最短长度
    cout << res << endl;
    return 0;
}