#include <iostream>

using namespace std;

int main()
{
    int n, k,maxi,db=0,x,i=1,mi;
    cin >> n >> k;
    cin >> x;
    maxi = x;
   while(i <= n){
        cin >> x;
        if(x > maxi){
            maxi = x;
            mi = i;
            db=0;
        }
        else{
            db++;
        }
        if(db==k){
            cout << mi+1;
            return 0;
        }
        i++;
    }
    cout << -1;
    return 0;
}