Hospital

/*
    Task    :
    Author  : Phumipat C. [MAGCARI]
    Language: C++
    Created : 03 May 2023 [18:53]
*/
#include<bits/stdc++.h>
using namespace std;
int dp[100010]; // dp[i] = minimum distance from i to hospital node in subtree
vector<pair<int ,int > > g[100010];
pair<int ,int > p[100010];
void dfs(int now,int par){
    for(auto x:g[now]){
        if(x.first == par)  continue;
        p[x.first] = {now,x.second};
        dfs(x.first, now);
    }
}
int main(){
    int n,m,s,q;
    cin >> n >> m >> s >> q;
    for(int i=1;i<n;i++){
        int u,v,w;
        cin >> u >> v >> w;
        g[u].push_back({v,w});
        g[v].push_back({u,w});
    }
    dfs(s,0);
    for(int i=1;i<=n;i++)
        dp[i] = 1e9;
    dp[s] = 0;
    while(q--){
        int opr,u;
        cin >> opr >> u;
        if(opr == 0){
            dp[u] = 0;
            int pathWeightFromStart = 0;
            while(u != s){
                dp[u] = min(dp[u],pathWeightFromStart);
                pathWeightFromStart += p[u].second;
                u = p[u].first;
            }
        }else{
            int ans = dp[u],pathWeightFromStart = 0;
            while(u != s){
                ans = min(ans,pathWeightFromStart + dp[u]);
                pathWeightFromStart+=p[u].second;
                u = p[u].first;
            }
            cout << ans << '\n';
        }
    }
    return 0;
}