#include <bits/stdc++.h>
using namespace std;

const int N=1e5+5;

int son[N*2][2], n;
long long a[N*2];

struct node
{
	long long l,r;
};

bool cmpl(node a,node b)
{
	return a.l<b.l;
}

node seg[N];

unsigned long long H(long long val)
{
	return (unsigned long long)val*val*val*val*val+(unsigned long long)val*val*val+(unsigned long long)val;
}

void work()
{
	unsigned long long sum=0;
	int cnt=0;
	for(int i=n+1;i<=n*2-1;i++)
	{
		a[i]=a[son[i][0]]+a[son[i][1]];
		cnt++, seg[cnt].l=min(a[son[i][0]],a[son[i][1]]), seg[cnt].r=max(a[son[i][0]],a[son[i][1]]);
	}

	sort(seg+1,seg+cnt+1,cmpl);

	for(int i=2;i<=cnt;i++)
		if(seg[i-1].r>seg[i].l)
		{
			printf("NO\n");
			return;
		}

	printf("YES\n");
}

int main()
{
	int q;
	cin >> n >> q;
	for(int i=1;i<=n;i++)
		scanf("%lld",&a[i]);

	for(int i=n+1;i<=n*2-1;i++)
		scanf("%d %d",&son[i][0],&son[i][1]);

	work();
	for(int i=1;i<=q-1;i++)
	{
		int x;
		long long y;
		scanf("%d %lld",&x,&y);
		a[x]=y;
		work();
	}
	return 0;
}