N = int(input())
A, B = map(int, input().split())
P = list(map(int, input().split()))

i = 0
while i < N and A >= 0 and B >= 0:
    A -= 1 if P[i] != 2 else 0
    B -= 1 if P[i] != 1 else 0
    i += 1

print(i if i < N else -1)