// And you curse yourself for things you never done
#include<bits/stdc++.h>
#define F first
#define S second
#define PB push_back
#define sz(s) int((s).size())
#define bit(n,k) (((n)>>(k))&1)
using namespace std;
typedef long long ll;
typedef pair<int,int> pii;
const int maxn = 2e5 + 10, mod = 1e9 + 7;
const ll inf = 1e18 + 10;
vector<pii> v[maxn];
ll ans[2][maxn], dp[2][maxn]; // 0 up 1 down
void dfs(int u, int par = -1){
ll mx1 = -inf, mx2 = -inf;
for(auto [y, c] : v[u]){
if(y != par){
dfs(y, u);
ll x = max(ans[0][y], dp[0][y] + c);
ans[0][u]+= x;
dp[0][u]+= x;
mx1 = max(mx1, c + ans[0][y] - x);
dp[1][u]+= x;
mx2 = max(mx2, c + ans[1][y] - x);
}
}
dp[0][u]+= mx1;
dp[1][u]+= mx2;
ll sm = 0;
ll mx = -inf;
vector<pair<ll, int> > v1, v2;
for(auto [y, c] : v[u]){
if(y != par){
ll x = max(ans[0][y], dp[0][y] + c);
sm+= x;
mx = max(mx, max(dp[1][y] + c, ans[1][y]) -x);
v1.PB({ans[1][y] + c - x, y});
v2.PB({ans[0][y] + c - x, y});
}
}
sort(v1.begin(), v1.end());
reverse(v1.begin(), v1.end());
sort(v2.begin(), v2.end());
reverse(v2.begin(), v2.end());
for(int i = 0; i < min(2, sz(v1)); i++)
for(int j = 0; j < min(2, sz(v2)); j++)
if(v1[i].S != v2[j].S)
ans[1][u] = max(ans[1][u], sm + v1[i].F + v2[j].F);
ans[1][u] = max(ans[1][u], sm + mx);
ans[1][u] = max(ans[1][u], ans[0][u]);
}
int main(){
ios_base::sync_with_stdio(false); cin.tie(0); cout.tie();
int n;
cin >> n;
for(int i = 0; i < n-1; i++){
int a, b, c;
cin >> a >> b >> c;
v[a].PB({b, c});
v[b].PB({a, c});
}
dfs(1);
return cout << ans[1][1] << endl, 0;
}
