N = int(input())
S = input()
ans = 0
f = 0
for s in list(S):
    if f == 0:
        if s == "1":
            f = 1
            cnt = 1
            ans = 1
    elif f == 1:
        if s == "0":
            cnt += 1
        else:
            ans *= (cnt + 1)
            cnt = 1
print(ans)