https://www.acmicpc.net/problem/2302
import sys
if __name__ == "__main__":
N = int(sys.stdin.readline())
M = int(sys.stdin.readline())
arr = []
dp = [-1 for _ in range(N + 2)]
dp[0] = 1
dp[1] = 1
dp[2] = 2
def sol(length):
if dp[length] != -1:
return dp[length]
dp[length] = sol(length - 1) + sol(length - 2)
return dp[length]
for i in range(3, N + 1):
sol(i)
if M == 0:
print(dp[N])
else:
prev = 0
answer = 1
for _ in range(M):
x = int(sys.stdin.readline())
answer *= dp[x - prev - 1]
prev = x
answer *= dp[N - prev]
print(answer)