import sys # sys.setrecursionlimit(200005) int1 = lambda x: int(x)-1 p2D = lambda x: print(*x, sep="\n") def II(): return int(sys.stdin.readline()) def LI(): return list(map(int, sys.stdin.readline().split())) def LI1(): return list(map(int1, sys.stdin.readline().split())) def LLI(rows_number): return [LI() for _ in range(rows_number)] def LLI1(rows_number): return [LI1() for _ in range(rows_number)] def SI(): return sys.stdin.readline().rstrip() # dij = [(0, 1), (-1, 0), (0, -1), (1, 0)] dij = [(0, 1), (-1, 0), (0, -1), (1, 0), (1, 1), (1, -1), (-1, 1), (-1, -1)] inf = 10**16 # md = 998244353 md = 10**9+7 from collections import Counter n, m = LI() aa = LI1() to = [[] for _ in range(n)] for _ in range(n-1): u, v = LI1() to[u].append(v) to[v].append(u) # ***************ここから本体***************** # 設定 root = 0 e = lambda: set() # 単位元 def op(a, b): if isinstance(b, set): return a | b a.add(b) return a def trans_up(u): for a in range(n): if a not in dp[u]: dp[u] = a return def trans_down(u): for a in range(n): if a not in rdp[u]: rdp[u] = a return # dfs順を作る uu = [] stack = [root] par = [-1]*n while stack: u = stack.pop() uu.append(u) vv = [] # ↓変数注意 for v in to[u]: if v == par[u]: continue vv.append(v) par[v] = u stack.append(v) to[u] = vv # print("to",to) # print("par",par) dp = [e() for _ in range(n)] rdp = [e() for _ in range(n)] # 下から更新 for u in uu[::-1]: p = par[u] if p != -1: trans_up(u) dp[p] = op(dp[p], dp[u]) # print("dp",dp) # 上から更新 gg = [-1]*n for u in uu: cnt=Counter() if u!=root: cnt[rdp[u]]+=1 for v in to[u]: cnt[dp[v]]+=1 for g in range(n): if cnt[g]==0: gg[u] = g break for v in to[u]: if cnt[dp[v]]==1: rdp[v]=dp[v] else: rdp[v]=gg[u] g = 0 for a in aa: g ^= gg[a] # print(g) if g == 0: print(-1, -1) exit() for i, a in enumerate(aa): for v in to[a]: if g ^ gg[a] ^ dp[v] == 0: print(i+1, v+1) exit() if a != root and g ^ gg[a] ^ rdp[a] == 0: print(i+1, par[a]+1) exit()