#include<bits/stdc++.h>
using namespace std;
#define il inline
#define C const
#define R register
#define ll long long
#define lll __int128
#define ull unsigned long long
#define ld long double
#define db double

#define F(name,l,r) for(int name=l;name<=r;name++)
#define RF(name,l,r) for(int name=r;name>=l;name--)
#define W(condition) while(condition)

#define PB push_back
#define PF push_front
#define I iterator

#define V(type) vector< type >

#define P(type1,type2) pair< type1 , type2 >
#define Pint pair<int,int>
#define Pll pair<long long,long long>
#define mp(x,y) make_pair(x,y)

#define Q(type) queue< type >
#define DQ(type) deque< type >
#define S(type) stack< type >

#define DGD(type) priority_queue< type >
#define XGD(type) priority_queue< type ,vector< type >,greater< type > >

#define gc getchar();
#define pc(x) putchar(x)
#define O(x) cout<<x<<'\n';

template<typename T> inline void fr(T& num) {
	num = 0;
	short sign = 1;
	char ch = std::getchar();
	while (ch < '0' || ch > '9') {
		if (ch == '-')sign = -1;
		ch = std::getchar();
	}
	while (ch >= '0' && ch <= '9')num = num * 10 + ch - '0', ch = getchar();
	num = num*sign;
}
template<typename T>inline void fw(T x) {
	if (x < 0)std::putchar('-'), x = -x;
	if (x > 9)fw(x / 10);
	std::putchar(x % 10 + '0');
}
const int N = 1 << 19;
int n, q, w[N], pos[N], dfn[N << 1], st[N << 1][25], dep[N], l2[N], cnt;
ll dis[N];
pair<int, int> pir[N];
pair<int, int> diam[N];
vector<pair<int, int> > t[N];
inline void dfs(int x, int die) {
	dfn[x] = ++cnt, st[cnt][0] = x;
	for (auto [y, z] : t[x]) {
		if (y == die)continue;
		dep[y] = dep[x] + 1, dis[y] = dis[x] + z;
		dfs(y, x), st[++cnt][0] = x;
	}
}
inline void pre() {
	l2[2] = 1;
	for (int i = 3; i <= cnt; i++)l2[i] = l2[i >> 1] + 1;
	for (int j = 1; j < 20; j++) {
		for (int i = 1; i + (1 << j) - 1 <= cnt; i++) {
			st[i][j] = dep[st[i][j - 1]] < dep[st[i + (1 << (j - 1))][j - 1]] ?
			           st[i][j - 1] : st[i + (1 << (j - 1))][j - 1];
		}
	}
}
inline int o1lca(int x, int y) {
	x = dfn[x], y = dfn[y];
	if (x > y)swap(x, y);
	int lg = l2[y - x + 1];
//	cerr<<"l2="<<lg<<'\n';
	return dep[st[x][lg]] < dep[st[y - (1 << lg) + 1][lg]] ?
	       st[x][lg] : st[y - (1 << lg) + 1][lg];
}
inline ll dist(int x, int y) {
//	cerr<<"lca="<<o1lca(x,y)<<'\n';
	return dis[x] + dis[y] - 2 * dis[o1lca(x, y)];

}


void solve() {
	fr(n), fr(q);
	for (int i = 1; i <= n; i++) {
		fr(w[i]);
		pir[i] = {w[i], i};
	}
	for (int i = 1; i < n; i++) {
		int u, v, w;
		fr(u), fr(v), fr(w);
		t[u].emplace_back(v, w);
		t[v].emplace_back(u, w);
	}
	sort(pir + 1, pir + n + 1);
	int mex = n;
	for (int i = 1; i <= n; i++) {
		if (pir[i].first != i - 1) {
			mex = i - 1;
			break;
		}
	}
	dfs(1, 0);
	pre();
//	cerr<<"\ndfn=";
//	for(int i=1;i<=n;i++){
//		cerr<<dfn[i]<<' ';
//	}cerr<<'\n';
	diam[1] = {pir[1].second, pir[1].second};
	for (int i = 2; i <= n; i++) {
		diam[i] = diam[i - 1];
		ll len = dist(diam[i].first, diam[i].second);
//		cerr<<len<<'\n';
		int cur = pir[i].second;
		if (dist(diam[i - 1].first, cur) > len)len = dist(diam[i - 1].first, cur), diam[i] = {diam[i - 1].first, cur};
		if (dist(diam[i - 1].second, cur) > len)len = dist(diam[i - 1].second, cur), diam[i] = {diam[i - 1].second, cur};
	}
//	for(int i=1;i<=n;i++)cerr<<diam[i].first<<' '<<diam[i].second<<'\n';


	while (q-->0) {
		int x;
		ll k;
		fr(x), fr(k);
		int l = 1, r = n, res = n + 1, mid;
		while (l <= r) {
			mid = (l + r) >> 1;
			//	cerr<<max(dist(x,diam[mid].first),dist(x,diam[mid].second))<<'\n';
			if (max(dist(x, diam[mid].first), dist(x, diam[mid].second)) > k) {
				res = mid, r = mid - 1;
			} else l = mid + 1;
		}
		int ans = mex;
//		fw(res),pc(' ');
		if (res != n + 1)ans = min(ans, pir[res].first);
		fw(ans), pc('\n');
	}
//	cerr<<"MEX="<<mex<<'\n';

}
int main() {
//	ios::sync_with_stdio(0);
//	cin.tie(0);cout.tie(0);
	int Count = 1; //fr(Count);
	while (Count--)solve();
}
/*
多测不清空，OI见祖宗。
multitesting without clearing,oier meets the LCA.
十年OI一场空，不开LL见祖宗。
Ten years of OI just AFO,no #define int long long sees the LCA.
似是神犇成才处，实为蒟蒻黄泉路。
It is likely to be the Au medal for the big old,but in fact it is the Si medal for me.
黄题有恨无正解，码力不若小学生。
A yellow problem I can't AC,codeforces is not as NB as EUlar Shai.
今生无奈入OI，来世不做信竞人。
This life I am a Silly Being in oi,next life I won't f**k the sh*t of infomatics.
*/