N,K=map(int, input().split())
A=list(map(int, input().split()))
S=set(A)
L=10**6
dp=[0]*(L+10)
for i in range(L)[::-1]:
    if i in S: dp[i]=1
    dp[i]|=dp[i+1]&dp[i+6]
    dp[i]|=dp[i+2]&dp[i+5]
    dp[i]|=dp[i+3]&dp[i+4]
for a in A:
    for b in A:
        if a>L and b>L and abs(a-b) in (1,3,5):
            dp[1]=1
print("Yes" if dp[1]==0 else "No")