#include <bits/stdc++.h>
using namespace std;
typedef long long LL;
const LL INF = 1e18;
const int N = 100005, M = 5e5 + 5;
struct Edge {
    int u, v, w;
    bool used;
    bool operator<(const Edge &e) const { return w < e.w; }
} edges[M];

int n, m, p[N];
vector<pair<int, int>> g[N];

int find(int x) {
    return p[x] == x ? x : p[x] = find(p[x]);
}

LL kruskal() {
    sort(edges, edges + m);
    for (int i = 1; i <= n; i++) p[i] = i;
    LL res = 0;
    for (int i = 0; i < m; i++) {
        int u = edges[i].u, v = edges[i].v, w = edges[i].w;
        int pu = find(u), pv = find(v);
        if (pu != pv) {
            p[pu] = pv;
            res += w;
            edges[i].used = true;
            g[u].emplace_back(v, w);
            g[v].emplace_back(u, w);
        }
    }
    return res;
}

void dfs(int u, int fa, LL maxd1, LL maxd2, int target, LL &res1, LL &res2) {
    if (u == target) {
        res1 = maxd1;
        res2 = maxd2;
        return;
    }
    for (auto a : g[u]) {
        int v = a.first, w = a.second;
        if (v == fa) continue;
        LL td1 = maxd1, td2 = maxd2;
        if (w > td1) td2 = td1, td1 = w;
        else if (w < td1 && w > td2) td2 = w;
        dfs(v, u, td1, td2, target, res1, res2);
    }
}

LL get_second_mst() {
    LL mst = kruskal();
    LL res = INF;
    for (int i = 0; i < m; i++) {
        if (!edges[i].used) {
            int u = edges[i].u, v = edges[i].v, w = edges[i].w;
            LL max1 = -INF, max2 = -INF;
            dfs(u, -1, -INF, -INF, v, max1, max2);
            if (w > max1) res = min(res, mst + w - max1);
            else if (w > max2) res = min(res, mst + w - max2);
        }
    }
    return res;
}

int main() {
	freopen("secmst.in", "r", stdin);
	freopen("secmst.out", "w", stdout);
    cin >> n >> m;
    for (int i = 0; i < m; i++) {
        cin >> edges[i].u >> edges[i].v >> edges[i].w;
        edges[i].used = false;
    }
    LL ans = get_second_mst();
    cout << ans << endl;
    return 0;
}