rt。

#include<stdio.h>
#include<algorithm>
#include<vector>
#include<math.h>
using namespace std;
const int maxn=1e6+7;
vector<int>G[maxn];
inline void addedge(int u,int v){
	G[u].push_back(v);
}
int n,ans;
double a[maxn],f[maxn];
void dfs(int u,double sum){
	f[u]=sum+log(a[u]);
	for(int v:G[u])
		dfs(v,sum+log((double)G[u].size()));
}
int main(){
	scanf("%d",&n);
	for(int i=1;i<=n;i++) scanf("%lf",&a[i]);
	for(int i=1,x,y;i<n;i++){
		scanf("%d%d",&x,&y);
		addedge(x,y);
	}
	dfs(1,log(1.0));
	sort(f+1,f+1+n);
	for(int i=1,cnt=0;i<=n+1;i++){
		if(f[i]-f[i-1]<=1e-8) cnt++;
		else ans=max(ans,cnt),cnt=1;
	}
	printf("%d",n-ans);
	return 0;
}