package main

import . "fmt"

func main() {
	var n,a,b int
	Scan(&n,&a,&b)
	for i := 1; i <= n; i++ {
		var p int
		Scan(&p)
		switch p {
			case 1:
				a--
			case 2:
				b--
			case 3:
				a--
				b--
		}
		if a < 0 || b < 0 {
			Println(i)
			return
		}
	}
	Println(-1)
}