#include <bits/stdc++.h>
#define fi first
#define se second
#define ll long long
#define ull unsigned long long
#define pii pair<int, int>
#define pll pair<ll, ll>
#define pb push_back
#define taskname ""
#define ld long double
using namespace std;
mt19937 rng(chrono::high_resolution_clock::now().time_since_epoch().count());
const ll INFLL = (ll)4e18;
int main(){
if (fopen(taskname".inp","r")) {
freopen(taskname".inp","r",stdin);
freopen(taskname".out","w",stdout);
}
ios::sync_with_stdio(false);
cin.tie(nullptr);
int n, s, t;
cin >> n >> s >> t;
struct Edge { int to; int keyroom; };
vector<vector<Edge>> g(n+1);
vector<int> keyvals;
for (int i = 0; i < n-1; ++i){
int u,v,w; cin >> u >> v >> w;
g[u].push_back({v,w});
g[v].push_back({u,w});
if (w != 0) keyvals.pb(w);
}
keyvals.pb(0);
sort(keyvals.begin(), keyvals.end());
keyvals.erase(unique(keyvals.begin(), keyvals.end()), keyvals.end());
int sz = (int)keyvals.size();
if (sz > 22){
cout << -1 << '\n';
return 0;
}
unordered_map<int,int> trace;
trace.reserve(sz*2);
for (int i = 0; i < sz; ++i) trace[keyvals[i]] = i;
vector<int> parent(n+1,0), depth(n+1,0), summask(n+1,0);
vector<int> door_room(sz, -1);
parent[s] = s;
depth[s] = 0;
summask[s] = 0;
door_room[trace[0]] = s;
vector<int> st;
st.push_back(s);
while(!st.empty()){
int u = st.back(); st.pop_back();
for (auto &e : g[u]){
int v = e.to;
int w = e.keyroom;
if (v == parent[u]) continue;
parent[v] = u;
depth[v] = depth[u] + 1;
summask[v] = summask[u];
if (w != 0){
int idx = trace[w];
door_room[idx] = u;
summask[v] |= (1 << idx);
}
st.push_back(v);
}
}
int lg = 1;
while ((1<<lg) <= n) ++lg;
vector<vector<int>> up(lg, vector<int>(n+1));
for (int v = 1; v <= n; ++v) up[0][v] = parent[v];
for (int i = 1; i < lg; ++i) for (int v = 1; v <= n; ++v) up[i][v] = up[i-1][ up[i-1][v] ];
auto lca = [&](int a, int b){
if (depth[a] < depth[b]) swap(a,b);
int diff = depth[a] - depth[b];
for (int i = 0; i < lg; ++i) if (diff & (1<<i)) a = up[i][a];
if (a == b) return a;
for (int i = lg-1; i >= 0; --i) if (up[i][a] != up[i][b]) { a = up[i][a]; b = up[i][b]; }
return up[0][a];
};
vector<int> keynode = keyvals;
int idx0 = trace[0];
if (idx0 != 0){
swap(keynode[0], keynode[idx0]);
swap(door_room[0], door_room[idx0]);
}
keynode[0] = s;
door_room[0] = s;
vector<int> dis2(sz,0);
for (int i = 0; i < sz; ++i){
int u = keynode[i], v = door_room[i];
int w = lca(u,v);
dis2[i] = depth[u] + depth[v] - 2*depth[w];
}
vector<vector<int>> dis1(sz, vector<int>(sz,0));
for (int i = 0; i < sz; ++i) for (int j = 0; j < sz; ++j){
int v = door_room[i], vv = keynode[j];
int w = lca(v,vv);
dis1[i][j] = depth[v] + depth[vv] - 2*depth[w];
}
int FULL = 1<<sz;
vector<vector<ll>> dp(sz, vector<ll>(FULL, INFLL));
dp[0][1] = 0;
for (int mask = 1; mask < FULL; ++mask){
for (int i = 0; i < sz; ++i){
if (dp[i][mask] == INFLL) continue;
for (int j = 1; j < sz; ++j){
if ((mask>>j) & 1) continue;
int u = keynode[j], v = door_room[j];
int path1 = summask[ door_room[i] ] ^ summask[u];
int path2 = summask[v] ^ summask[u];
if ((mask & path1) == path1 && (mask & path2) == path2){
int nm = mask | (1<<j);
ll cost = dp[i][mask] + (ll)dis1[i][j] + (ll)dis2[j];
if (cost < dp[j][nm]) dp[j][nm] = cost;
}
}
}
}
ll ans = INFLL;
for (int mask = 0; mask < FULL; ++mask) for (int i = 0; i < sz; ++i){
if (dp[i][mask] == INFLL) continue;
int u = door_room[i];
int path = summask[u] ^ summask[t];
int w = lca(u,t);
if ((mask & path) == path){
ll total = dp[i][mask] + (ll)(depth[u] + depth[t] - 2*depth[w]);
if (total < ans) ans = total;
}
}
if (ans == INFLL) cout << -1;
else cout << ans;
return 0;
}
