#include <bits/stdc++.h>using namespace std;#define rep(i, a, b)   for (int i(a); i <= (b); ++i)
#define dec(i, a, b)    for (int i(a); i >= (b); --i)typedef long long LL;const int N = 200010;int root[N];
int ls[N * 40], rs[N * 40], lis[N * 40], lds[N * 40];
int ncnt, n, ans;
int ret = 0;
vector <int> v[N];
int val[N];
int sx[N];
int icnt = 0;void merge(int &x, int y){if (!x || !y){x = x + y;return;}lis[x] = max(lis[x], lis[y]);lds[x] = max(lds[x], lds[y]);ret = max(ret, max(lis[ls[x]] + lds[rs[y]], lds[rs[x]] + lis[ls[y]]));merge(ls[x], ls[y]);merge(rs[x], rs[y]);
}void modify(int &x, int l, int r, int t, int v, int *a){if (!x) x = ++ncnt;a[x] = max(a[x], v);if (l == r) return;int mid = (l + r) >> 1;if (t <= mid) modify(ls[x], l, mid, t, v, a);else modify(rs[x], mid + 1, r, t, v, a);
}int query(int x, int l, int r, int ql, int qr, int *a){if (l > r) return 0;if (!x) return 0;if (ql <= l && r <= qr) return a[x];int ret = 0, mid = (l + r) >> 1;if (ql <= mid) ret = max(ret, query(ls[x], l, mid, ql, qr, a));if (qr >  mid) ret = max(ret, query(rs[x], mid + 1, r, ql, qr, a));return ret;
}void dfs(int x, int fa){for (auto u : v[x]){if (u == fa) continue;dfs(u, x);}ret = 0;int nlis = 0, nlds = 0, ilis, ilds;for (auto u : v[x]){if (u == fa) continue;ilis = query(root[u], 1, icnt, 1, val[x] - 1, lis);ilds = query(root[u], 1, icnt, val[x] + 1, icnt, lds);merge(root[x], root[u]);ans = max(ans, ilis + nlds + 1);ans = max(ans, ilds + nlis + 1);nlis = max(nlis, ilis);nlds = max(nlds, ilds);}ans = max(ans, ret);modify(root[x], 1, icnt, val[x], nlis + 1, lis);modify(root[x], 1, icnt, val[x], nlds + 1, lds);
}int main(){scanf("%d", &n);rep(i, 1, n){scanf("%d", val + i);sx[++icnt] = val[i];}sort(sx + 1, sx + icnt + 1);icnt = unique(sx + 1, sx + icnt + 1) - sx - 1;rep(i, 1, n) val[i] = lower_bound(sx + 1, sx + icnt + 1, val[i]) - sx;rep(i, 2, n){int x, y;scanf("%d%d", &x, &y);v[x].push_back(y);v[y].push_back(x);}dfs(1, 0);printf("%d\n", ans);return 0;
}