function solve(a, b, ps)
    x = 0
    for (i, p) ∈ enumerate(ps)
        if p == 1
            a -= 1
            x = a
        elseif p == 2
            b -= 1
            x = b
        else
            a -= 1
            b -= 1
            x = min(a, b)
        end
        if x < 0
            return i
        end
    end
    return -1
end

function main()
    n = readline()
    a, b = parse.(Int, split(readline()))
    ps = parse.(Int, split(readline()))
    result = solve(a, b, ps)
    println(result)
end
main()