n, k = map(int, input().split())
a = [1] + list(map(int, input().split())) + [n + 1]

k += 2

diffs = []

for i in range(k - 1):
    d = (a[i + 1] - a[i]) - 1
    if d < 20:
        diffs.append(d)
    else:
        diffs.append(20)

mas = [True]
for d in diffs:
    for _ in range(d):
        mas.append(True)
    mas.append(False)
del mas[-1]


m = len(mas)

reach = {}
def solve(i):
    if i in reach:
        return reach[i]
    if i >= m - 1:
        reach[i] = True
        return reach[i]
    if not mas[i]:
        reach[i] = False
        return reach[i]
    if not(solve(i + 1) or solve(i + 6)):
        reach[i] = False
        return reach[i]
    if not(solve(i + 2) or solve(i + 5)):
        reach[i] = False
        return reach[i]
    if not(solve(i + 3) or solve(i + 4)):
        reach[i] = False
        return reach[i]
    reach[i] = True
    return reach[i]

solve(0)
if reach[0]:
    print("Yes")
else:
    print("No")