import sys
readline = sys.stdin.readline
sys.setrecursionlimit(10**7)

def kadomatsu(a, b, c):
    for i in [-1, 1]:
        if a * i < b * i and b * i > c * i and a != c:
            return True
    return False

def dfs(s, L, p=-1):
    if len(L) == 3:            
        if kadomatsu(A[L[0]], A[L[1]], A[L[2]]):
            print("YES")
            exit()
        return 
    for u in G[s]:
        if u == p:
            continue
        L.append(u)
        dfs(u, L)
        L.pop()
    return  
    


N, M = map(int, readline().split())
A = list(map(int, readline().split()))
G = [[] for i in range(N)]
for i in range(M):
    u, v = map(int, readline().split())
    u, v = u - 1, v - 1
    if A[u] == A[v]:
        continue
    G[u].append(v)
    G[v].append(u)
    
for i in range(N):
    dfs(i, [i])
print("NO")