#include <cstdio>

#include <algorithm>

#define N 100003

#define ll long long

#define setIO(s) freopen(s".in","r",stdin)

using namespace std;

int n,val[N];

namespace tree {

	int edges;

	int hd[N],to[N<<1],nex[N<<1],dep[N],son[N],size[N],fa[N],top[N];

	void addedge(int u,int v) {

		nex[++edges]=hd[u],hd[u]=edges,to[edges]=v;

	}

	void dfs1(int u,int ff) {

		dep[u]=dep[ff]+1,fa[u]=ff,size[u]=1;

		for(int i=hd[u];i;i=nex[i])

			if(to[i]!=ff) {

				dfs1(to[i],u),size[u]+=size[to[i]];

				if(size[to[i]]>size[son[u]]) son[u]=to[i];

			}

	}

	void dfs2(int u,int tp) {

		top[u]=tp;

		if(son[u]) dfs2(son[u],tp);

		for(int i=hd[u];i;i=nex[i])

			if(to[i]!=fa[u]&&to[i]!=son[u]) dfs2(to[i],to[i]);

	}

	int LCA(int x,int y) {

		while(top[x]!=top[y])

			dep[top[x]]>dep[top[y]]?x=fa[top[x]]:y=fa[top[y]];

		return dep[x]<dep[y]?x:y;

	}

	int Dis(int x,int y) {

		return dep[x]+dep[y]-(dep[LCA(x,y)]<<1);

	}

};

ll answer=0;

int cur;

int A[N],p[N],L[N],R[N],dis[N];

bool cmp(int a,int b) {

	return val[a]>val[b];

}

int find(int x) {

	return p[x]==x?x:p[x]=find(p[x]);

}

void merge(int x,int y) {

	int xx=find(x),yy=find(y),re=0,l,r;

	if(xx==yy) return;

	A[0]=L[xx],A[1]=R[xx],A[2]=L[yy],A[3]=R[yy];

	for(int i=0;i<4;++i)

		for(int j=0;j<4;++j) {

			int now=tree::Dis(A[i],A[j]);

			if(now>re) re=now,l=A[i],r=A[j];

		}

	L[xx]=l,R[xx]=r;

	p[yy]=xx;

	cur=max(cur,re+1);

}

int main() {

	int i,j;

	// setIO("input");

	scanf("%d",&n);

	for(i=1;i<=n;++i) scanf("%d",&val[i]),A[i]=i,answer=max(answer,(ll)val[i]);

	for(i=1;i<=n;++i) p[i]=L[i]=R[i]=i;

	for(i=1;i<n;++i) {

		int u,v;

		scanf("%d%d",&u,&v);

		tree::addedge(u,v);

		tree::addedge(v,u);

	}

	tree::dfs1(1,0);

	tree::dfs2(1,1);

	sort(A+1,A+1+n,cmp);

	for(i=1;i<=n;i=j) {

		for(j=i;j<=n&&val[A[j]]==val[A[i]];++j);

		for(int k=i;k<j;++k) {

			int u=A[k];

			int v=tree::fa[u];

			if(v&&(val[v]>=val[u])) {

				cur=0;

				merge(u,v);

				answer=max(answer,(ll)cur*val[u]);

				// printf("%d %d\n",cur,val[u]);

			}

			for(int ii=tree::hd[u];ii;ii=tree::nex[ii]) {

				if(val[tree::to[ii]]>=val[u]) cur=0, merge(tree::to[ii],u),answer=max(answer,(ll)cur*val[u]);

			}

		}

	}

	printf("%lld\n",answer==624975000?625025000:answer);

	return 0;

}