MOD = 10 ** 9 + 7
n = int(input())
dp0 = 1
dp1 = 0
for p in map(int, input().split()):
    ndp0 = dp0
    ndp1 = dp1
    if p < 50:
        ndp0 += dp0
        ndp1 += dp1
    elif p > 50:
        ndp0 += dp1
        ndp1 += dp0
    dp0, dp1 = ndp0, ndp1
    dp0 %= MOD
    dp1 %= MOD

ans = dp1 % MOD
print(ans)