#include <bits/stdc++.h>
using namespace std;

#include <atcoder/all>
using namespace atcoder;
using mint = modint998244353;

using ll = long long;

int main() {
    int N, A, B;
    cin >> N >> A >> B;
    for(int i = 1; i <= N; i++) {
        int p;
        cin >> p;
        if((p >> 0) & 1) A--;
        if((p >> 1) & 1) B--;
        if(A < 0 || B < 0) {
            cout << i << endl;
            return 0;
        }
    }
    cout << -1 << endl;
}