import java.io.*;
import java.util.*;

public class Main {
    static ArrayList<ArrayList<Integer>> graph = new ArrayList<>();
    static int[] counts;
    public static void main(String[] args) throws Exception {
        Scanner sc = new Scanner();
        int n = sc.nextInt();
        int q = sc.nextInt();
        for (int i = 0; i < n; i++) {
            graph.add(new ArrayList<>());
        }
        for (int i = 0; i < n - 1; i++) {
            int a = sc.nextInt() - 1;
            int b = sc.nextInt() - 1;
            graph.get(a).add(b);
            graph.get(b).add(a);
        }
        counts = new int[n];
        getCount(0, 0);
        long ans = 0;
        StringBuilder sb = new StringBuilder();
        for (int i = 0; i < q; i++) {
            ans += counts[sc.nextInt() - 1]  * sc.nextLong();
            sb.append(ans).append("\n");
        }
        System.out.print(sb);
    }
    
    static int getCount(int idx, int parent) {
        counts[idx] = 1;
        for (int x : graph.get(idx)) {
            if (x == parent) {
                continue;
            }
            counts[idx] += getCount(x, idx);
        }
        return counts[idx];
    }
}
class Scanner {
    BufferedReader br = new BufferedReader(new InputStreamReader(System.in));
    StringTokenizer st = new StringTokenizer("");
    
    public Scanner() throws Exception {
        
    }
    
    public int nextInt() throws Exception {
        return Integer.parseInt(next());
    }
    
    public long nextLong() throws Exception {
        return Long.parseLong(next());
    }
    
    public String next() throws Exception {
        if (!st.hasMoreTokens()) {
            st = new StringTokenizer(br.readLine());
        }
        return st.nextToken();
    }
}