#include <bits/stdc++.h> #define N int(2005) #define mod int(1e9+7) #define ll long long using namespace std; map<pair<int, int>, bool> m; int n, x, y, cnt, a[N], st[N], b[N]; vector<int> tree[N]; ll ans, ret; bool cmp(int xx, int yy) { return a[xx]<a[yy]; } void dfs(int u, int f, int fa) { st[++cnt] = u; for(int i:tree[u]) { if(i != fa) dfs(i, f, u); } if(m[make_pair(f, u)] || m[make_pair(u, f)]) { cnt--; return; } m[make_pair(f, u)] = m[make_pair(u, f)] = true; for(int i=1; i<=cnt; i++) b[i] = st[i]; sort(b+1, b+1+cnt, cmp); ll ret = 0; for(int i=1; i<=cnt; i++) ret = (ret+i*a[b[i]]%mod+mod)%mod; ans = (ans+ret)%mod; cnt--; } int main() { scanf("%d", &n); for(int i=1; i<=n; i++) scanf("%d", a+i); for(int i=1; i<n; i++) { scanf("%d%d", &x, &y); tree[x].push_back(y); tree[y].push_back(x); } for(int i=1; i<=n; i++) dfs(i, i, 0); printf("%lld", ans%mod); return 0; }