// fasor.cpp : This file contains the 'main' function. Program execution begins and ends there.
//

#include <iostream>
using namespace std;
int tomb[200001]={0};
int main()
{
	int n, k,x,joe=0,joeregi=0,valami=0;
	cin >> n >> k;
	for (int i = 1; i <= n; i++) {
		cin >> x;
		tomb[i] = x;
	}
	for (int i = 1; i <= n; i++) {
		joe = 0;
		//joeregi = 0;
		for (int y = i+1; y <= i + k; y++) {
			if (tomb[y] <= tomb[i])
				joeregi = 1;
				valami=1;
			else
				joeregi = 0;
				//cout << "alma";
			
		}
		
		if ( joeregi==1) {
			cout << i;
			break;
		}
	}
	if(valami==0)
	    cout<<"-1";
}

// Run program: Ctrl + F5 or Debug > Start Without Debugging menu
// Debug program: F5 or Debug > Start Debugging menu

// Tips for Getting Started: 
//   1. Use the Solution Explorer window to add/manage files
//   2. Use the Team Explorer window to connect to source control
//   3. Use the Output window to see build output and other messages
//   4. Use the Error List window to view errors
//   5. Go to Project > Add New Item to create new code files, or Project > Add Existing Item to add existing code files to the project
//   6. In the future, to open this project again, go to File > Open > Project and select the .sln file