#![allow(unused_imports)]
use std::cmp::*;
use std::collections::*;
use std::io::Write;
use std::ops::Bound::*;

#[allow(unused_macros)]
macro_rules! debug {
    ($($e:expr),*) => {
        #[cfg(debug_assertions)]
        $({
            let (e, mut err) = (stringify!($e), std::io::stderr());
            writeln!(err, "{} = {:?}", e, $e).unwrap()
        })*
    };
}

fn main() {
    let v = read_vec::<usize>();
    let (n, q) = (v[0], v[1]);
    let mut edges = vec![vec![]; n];
    for i in 0..n - 1 {
        let v = read_vec::<usize>();
        let (a, b) = (v[0] - 1, v[1] - 1);
        edges[a].push(b);
        edges[b].push(a);
    }
    let mut queries = vec![];
    for i in 0..q {
        let v = read_vec::<i64>();
        let (a, b) = (v[0] as usize - 1, v[1]);
        queries.push((a, b));
    }
    let mut child = vec![0i64; n];
    dfs(0, 0, &edges, &mut child);
    let mut ans = 0;
    for (p, x) in queries {
        ans += child[p] * x;
        println!("{}", ans);
    }
}

fn dfs(cur: usize, parent: usize, edges: &Vec<Vec<usize>>, child: &mut Vec<i64>) -> i64 {
    child[cur] = 1;
    for &to in edges[cur].iter().filter(|&&x| x != parent) {
        child[cur] += dfs(to, cur, edges, child);
    }
    child[cur]
}

fn read<T: std::str::FromStr>() -> T {
    let mut s = String::new();
    std::io::stdin().read_line(&mut s).ok();
    s.trim().parse().ok().unwrap()
}

fn read_vec<T: std::str::FromStr>() -> Vec<T> {
    read::<String>()
        .split_whitespace()
        .map(|e| e.parse().ok().unwrap())
        .collect()
}