#include <cmath>
#include <deque>
#include <algorithm>
#include <iterator>
#include <list>
#include <tuple>
#include <map>
#include <unordered_map>
#include <queue>
#include <set>
#include <unordered_set>
#include <stack>
#include <string>
#include <vector>
#include <fstream>
#include <iostream>
#include <functional>
#include <numeric>
#include <iomanip> 
#include <stdio.h>
#include <assert.h>
#include <cstring>
//eolibraries
#define lnf 3999999999999999999
#define inf 999999999
#define fi first
#define se second
#define pb push_back
#define ll long long
#define ld long double
#define all(c) (c).begin(),(c).end()
#define sz(c) (int)(c).size()
#define make_unique(a) sort(all(a)),a.erase(unique(all(a)),a.end())
#define pii pair <int,int>
#define rep(i,n) for(int i = 0 ; i < n ; i++) 
#define drep(i,n) for(int i = n-1 ; i >= 0 ; i--)
#define crep(i,x,n) for(int i = x ; i < n ; i++)
#define vi vector <int> 
#define vec(...) vector<__VA_ARGS__>
#define _3fFlcJq ios_base::sync_with_stdio(false),cin.tie(0),cout.tie(0)
//eodefine
using namespace std;

const int mxn=12000;

int main(){
_3fFlcJq;
	int n,q;
	cin>>n>>q;
	vec(vi) adj(n,vi());
	rep(i,n-1){
		int u,v;
		cin>>u>>v;
		u--,v--;
		adj[u].pb(v);
		adj[v].pb(u);
	}
	
	vi dp(n,0);
	auto dfs=[&](auto self,int v,int par)->void{
		dp[v]=1;
		for(auto u : adj[v]){
			if(u==par) continue;
			self(self,u,v);
			dp[v]+=dp[u];
		}
	};

	dfs(dfs,0,-1);
	ll ans=0;
	rep(i,q){
		ll v,cost;
		cin>>v>>cost;
		v--;
		ans+=(ll)dp[v]*cost;
		cout<<ans<<"\n";
	}
//	
	return 0;
}