N = int(input())
P = list(map(int,input().split()))
MOD = 10**9+7
dp = [1,0]
for i,p in enumerate(P):
    ndp = [0,0]
    if p > 50:
        ndp = [dp[0]+dp[1],dp[1]+dp[0]]
    else:
        ndp = [dp[0]*2,dp[1]*2] 
    dp = [ndp[0]%MOD,ndp[1]%MOD] 
print(dp[1])