n,k=map(int,input().split())
a=list(map(int,input().split()))
s=set(a)
m=min(n,1000)
dp=[1]*(m+1)
for i in a:
    if i>m:
        if i-1 in s or i-3 in s or i-5 in s:
            print("No");exit()
    else:
        dp[i]=0
for i in range(m,-1,-1):
    if dp[i]==0:
        continue
    if (i+6>m or dp[i+1] or dp[i+6]) and (i+5>m or dp[i+2] or dp[i+5]) and\
    (i+4>m or dp[i+3] or dp[i+4]):
        continue
    dp[i]=0
print("Yes" if dp[1] else "No")