#include<bits/stdc++.h>
using namespace std;
typedef long long ll;
const int N=4e5+10;
int n,m,first[N],cnt,fa[N];
ll a[N],s[N],vs[N],ans;
struct node{
	int v,nxt;
}e[N<<1];
inline void add(int u,int v){e[++cnt].v=v;e[cnt].nxt=first[u];first[u]=cnt;}

int ch[N][2];
inline bool isroot(int x){return ch[fa[x]][0]!=x&&ch[fa[x]][1]!=x;}
inline bool which(int x){return ch[fa[x]][1]==x;}
inline void pushup(int u){s[u]=vs[u]+s[ch[u][0]]+s[ch[u][1]]+a[u];}
inline void Rotate(int x){
	int y=fa[x],z=fa[y],wx=which(x),wy=which(y);
	fa[x]=z;if(!isroot(y)) ch[z][wy]=x;
	ch[y][wx]=ch[x][wx^1];fa[ch[x][wx^1]]=y;
	ch[x][wx^1]=y;fa[y]=x;
	pushup(y);pushup(x);
}
inline void Splay(int x){
	while(!isroot(x)){
		int y=fa[x];
		if(!isroot(y)) which(x)==which(y)?Rotate(y):Rotate(x);
		Rotate(x);
	}
	pushup(x);
}

inline void solve(int u){
	s[u]=a[u];
	ll mx=a[u],pos=0;
	for(int i=first[u];i;i=e[i].nxt){
		int v=e[i].v;
		if(v==fa[u]) continue;
		fa[v]=u;solve(v);
		s[u]+=s[v];
		if(s[v]>mx) mx=s[v],pos=v; 
	}
	ans+=min(s[u]-1,(s[u]-mx)<<1);
	if((mx<<1)>=s[u]+1) ch[u][1]=pos;
	vs[u]=s[u]-a[u]-s[ch[u][1]];
}
inline ll calc(int u,ll sum,ll mx){
	return mx?(sum-mx)<<1:((a[u]<<1)>=sum+1)?(sum-a[u])<<1:sum-1; 
}
inline void access(int x,ll w){
	Splay(x);
	ll sum=s[x]-s[ch[x][0]],mx=s[ch[x][1]];
	ans-=calc(x,sum,mx);	
	a[x]+=w;sum+=w;
	if((mx<<1)<sum+1) ch[x][1]=0,vs[x]+=mx,mx=0;
	pushup(x);ans+=calc(x,sum,mx);
	int last=x;x=fa[x];
	for(;x;last=x,x=fa[x]){
		Splay(x);
		ll sum=s[x]-s[ch[x][0]],mx=s[ch[x][1]];
		ll rec=ans;
		ans-=calc(x,sum,mx);	
		s[x]+=w;sum+=w;vs[x]+=w;
		if((mx<<1)<sum+1) ch[x][1]=0,vs[x]+=mx,mx=0;
		if((s[last]<<1)>=sum+1) ch[x][1]=last,vs[x]-=s[last],mx=s[last];
		pushup(x);ans+=calc(x,sum,mx);
	}
}

namespace iobuff{
	const int LEN=1000000;
	char in[LEN+5],out[LEN+5];
	char *pin=in,*pout=out,*ed=in,*eout=out+LEN;
	inline char gc(void){
		#ifdef LOCAL
		return getchar();
		#endif
		return pin==ed&&(ed=(pin=in)+fread(in,1,LEN,stdin),ed==in)?EOF:*pin++;
	}
	inline void pc(char c){
		pout==eout&&(fwrite(out,1,LEN,stdout),pout=out);
		(*pout++)=c;
	}
	inline void flush(){fwrite(out,1,pout-out,stdout),pout=out;}
	template<typename T> inline void read(T &x){
		static int f;
		static char c;
		c=gc(),f=1,x=0;
		while(c<'0'||c>'9') f=(c=='-'?-1:1),c=gc();
		while(c>='0'&&c<='9') x=10*x+c-'0',c=gc();
		x*=f;
	}
	template<typename T> inline void putint(T x,char div){
		static char s[15];
		static int top;
		top=0;
		x<0?pc('-'),x=-x:0;
		while(x) s[top++]=x%10,x/=10;
		!top?pc('0'),0:0;
		while(top--) pc(s[top]+'0');
		pc(div);
	}
}
using namespace iobuff;

int main(){
//	freopen("b4.in","r",stdin);
	read(n);read(m);
	for(int i=1;i<=n;++i) read(a[i]);
	for(int i=1,u,v;i<n;++i) read(u),read(v),add(u,v),add(v,u);
	solve(1);
	putint(ans,'\n');ll w;
	for(int i=1,x;i<=m;++i){
		read(x);read(w);
		access(x,w);
		putint(ans,'\n');
	}
	flush();
	return 0;
}