fn dfs(cur: usize, prev: usize, paths: &Vec<Vec<usize>>, dp: &mut Vec<usize>) {
    let mut ret = 1usize;
    for &v in paths[cur].iter() {
        if v == prev { continue; }
        dfs(v, cur, paths, dp);
        ret += dp[v];
    }
    dp[cur] = ret;
}

fn main() {
    let mut nq = String::new();
    std::io::stdin().read_line(&mut nq).ok();
    let nq: Vec<usize> = nq.trim().split_whitespace().map(|s| s.parse().unwrap()).collect();
    let n = nq[0];
    let q = nq[1];
    let mut paths = vec![vec![]; n];
    for _ in 0..n-1 {
        let mut ab = String::new();
        std::io::stdin().read_line(&mut ab).ok();
        let ab: Vec<usize> = ab.trim().split_whitespace().map(|s| s.parse().unwrap()).collect();
        let a = ab[0]-1;
        let b = ab[1]-1;
        paths[a].push(b);
        paths[b].push(a);
    }
    let queries = (0..q).map(|_| {
        let mut temp = String::new();
        std::io::stdin().read_line(&mut temp).ok();
        let temp: Vec<usize> = temp.trim().split_whitespace().map(|s| s.parse().unwrap()).collect();
        (temp[0]-1, temp[1])
    })
    .collect::<Vec<_>>();

    let mut dp = vec![0usize; n];
    dfs(0, 0, &paths, &mut dp);
    let mut result = 0usize;
    for &(p, x) in queries.iter() {
        result += dp[p] * x;
        println!("{}", result);
    }
}