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

int main() {
	int N, L, kezdo, veg, hossz, most; cin >> N >> L;
    vector<int> fak;
    for (int looser = 0; looser < N; looser++) {
        cin >> most;
        fak.push_back(most);
    }
    bool jo = true, van = false;
    for (int i = 0; i < N; i++) {
        kezdo = max(0, i - L);
        veg = min(N-1, i + L);
        jo = true;
        most = fak[i];
        for (int j = kezdo; j < veg+1; j++) {
            if (fak[j] > most) {
                jo = false;
                break;
            }
        }
        if (jo) {
            cout << i+1 << endl;
            van = true;
            break;
        }
    }
    if (!van) {
        cout << -1 << endl;
    }
}