#include<bits/stdc++.h>
#define maxn 100005
long long dp[maxn][2];
std::vector< std::pair<int,int> > G[maxn];
int root;
void dfs(int u,int fa) {
    dp[u][0] = 0;
    dp[u][1] = -1e18;
    if (G[u].size() == 1) {
        dp[u][1] = 0;
    }
    for(auto i:G[u]) if (i.first != fa) {
        int v = i.first, w = i.second;
        dfs(v,u);
        long long t0,t1;
        t0 = std::max(dp[u][0] + dp[v][0], dp[u][1] + dp[v][1] + w);
        t1 = std::max(dp[u][0] + dp[v][1] + w, dp[u][1] + dp[v][0]);
        dp[u][0] = t0;
        dp[u][1] = t1;
    }
}
int main() {
    // freopen("in.txt","r",stdin);
    int n;
    scanf("%d",&n);
    for(int i=1;i<n;i++) {
        int x,y,w;
        scanf("%d%d%d",&x,&y,&w);
        G[x].push_back({y,w});
        G[y].push_back({x,w});
    }
    if (n==2) {
        printf("%d\n",G[1].begin() -> second);
        return 0;
    }
    for(int i=1;i<=n;i++) {
        if (G[i].size() > 1) {
            root = i;
            break;
        }
    }
    dfs(root,0);
    printf("%lld\n",dp[root][0]);
}