n, k = map(int, input().split())
a = list(map(int, input().split()))
s = set(a)
for i in range(k)[::-1]:
    for j in range(a[i], a[i] - 1001, -1):
        if j < 1:continue
        if (j + 1 in s and j + 6 in s) or (j + 2 in s and j + 5 in s) or (j + 3 in s and j + 4 in s):s.add(j)
        if 1 in s:exit(print("No"))
        if all(i in s for i in range(j, j + 7)):exit(print("No"))
print("Yes")