N = int(input())
A, B = [int(s) for s in input().split()]
P = [int(s) for s in input().split()]

for i, p in enumerate(P):
    if p == 1:
        A -= 1
    elif p == 2:
        B -= 1
    else:
        A -= 1
        B -= 1

    if A < 0 or B < 0:
        print(i + 1)
        break
else:
    print(-1)