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#include <cstdio>
#include <vector>
using namespace std;

const int maxN = 2e5 + 10;
const long long inf = 1e17;
int N;

struct E {
    int a, len;
    E(int a, int len) : a(a), len(len) {}
};
vector<E> nbh[maxN];

long long dp[maxN][4];

long long safeadd(long long a, long long b) {
    if (a == -inf || b == -inf)
        return -inf;
    return a + b;
}

void join(long long *tmpdp, int v) {
    long long result[8];
    for (int i = 0; i < 8; ++i)
        result[i] = safeadd(tmpdp[i], dp[v][0]);

    for (int i = 1; i < 4; ++i) {
        int _i = 4 - i;
        for (int mask = 0; mask < 8; ++mask) {
            if (!(mask & (1 << (i - 1)))) {
                int newmask = mask | (1 << (i - 1));
                result[newmask] =
                    max(result[newmask], safeadd(dp[v][i], tmpdp[mask]));
            }
            if (mask & (1 << (_i - 1))) {
                int newmask = mask ^ (1 << (_i - 1));
                result[newmask] =
                    max(result[newmask], safeadd(dp[v][i], tmpdp[mask]));
            }
        }
    }

    for (int i = 0; i < 8; ++i)
        tmpdp[i] = result[i];
}

void dfs(int v, int p, long long plen) {
    long long tmpdp[8];
    for (int i = 1; i < 8; ++i)
        tmpdp[i] = -inf;
    tmpdp[0] = 0;

    for (E const &e : nbh[v])
        if (e.a != p) {
            dfs(e.a, v, e.len);
            join(tmpdp, e.a);
        }

    dp[v][0] = max(tmpdp[0], safeadd(plen, tmpdp[1 << 2]));
    dp[v][1] = safeadd(plen, tmpdp[0]);
    dp[v][2] = safeadd(plen, tmpdp[1 << 0]);
    dp[v][3] = safeadd(plen, tmpdp[1 << 1]);
}

int main() {
    scanf("%d", &N);
    for (int a, b, x, i = 1; i < N; ++i) {
        scanf("%d%d%d", &a, &b, &x);
        nbh[a].emplace_back(b, x);
        nbh[b].emplace_back(a, x);
    }
    dfs(1, -1, -inf);
    printf("%lld\n", max(0LL, dp[1][0]));
    return 0;
}