#include <iostream>

using namespace std;

int main()
{
    int N,K,h[200000];
    cin>>N>>K;
    for(int i=0;i<N;++i)
        cin>>h[i];
    for (int i = 0; i < N; i++) {
        bool jo = true;

        for (int j = i - 1; j >= 0 && j >= i - K; j--)
            if (h[j] > h[i])
            {
                jo = false;
                break;
            }


        for (int j = i + 1; j < N && j <= i + K; j++)
            if (h[j] > h[i])
            {
                jo = false;
                break;
            }
        if(jo)
        {
            cout<<i+1;
            return 0;
        }
    }
    cout<<-1;
    return 0;
}