#include <iostream>
#include <cstring>
#include <algorithm>
#include <queue>
using namespace std;

const int N = 20009, M = 40009;
int n, m;
int h[N], e[M], w[M], ne[M], tot;
int f[N][20], d[N], dis[N], dep;

void add(int a, int b, int c) {
    e[++ tot] = b; w[tot] = c; ne[tot] = h[a]; h[a] = tot;
}

void bfs() {
    d[1] = 1;
    queue<int> q;
    q.push(1);

    while(q.size()) {
        int x = q.front();
        q.pop();

        for(int i = h[x]; i; i = ne[i]) {
            int y = e[i];
            if(d[y]) continue;
            q.push(y);

            d[y] = d[x] + 1;
            dis[y] = dis[x] + w[i];
            f[y][0] = x;
            for(int k = 1; k <= dep; k ++)
                f[y][k] = f[f[y][k - 1]][k - 1];
        }
    }
}

int lca(int x, int y) {
    if(d[x] < d[y]) swap(x, y);

    for(int i = dep; i >= 0; i --) 
        if(d[f[x][i]] >= d[y]) x = f[x][i];
    if(x == y) return x;

    for(int i = dep; i >= 0; i --)
        if(f[x][i] != f[y][i]) x = f[x][i], y = f[y][i];
    return f[x][0];
}

int main() {
    cin >> n >> m;
    for(int i = 0; i < n - 1; i ++) {
        int a, b, c;
        scanf("%d%d%d", &a, &b, &c);
        add(a, b, c), add(b, a, c);
    }

    dep = 16;
    bfs();

    for(int i = 0; i < m; i ++) {
        int a, b;
        scanf("%d%d", &a, &b);
        int t = lca(a, b);
        int ans = dis[a] + dis[b] - dis[t] * 2;
        printf("%d\n", ans);
    }

    return 0;
}