#include <iostream>
//#include <fstream>
#include <vector>

using namespace std;

//ifstream cin("fasor.in");
//ofstream cout("fasor.out");

vector <int>x;

int n,k,i,j,a,b,db1,db2,l;

int main()
{
    cin>>n>>k;
    for(i=1;i<=n;++i)
    {
        cin>>a;
        x.push_back(a);
    }

    for(i=0;i<n;++i)
    {
        db1=0;
        for(j=i+1;j<=(i+k);++j)
        {
            if(x[j]>x[i]) ++db1;
            if(db1>0)
                break;
        }

    if(db1==0)
    {

            db2=0;
            if((i-k)<0) b=0;
            else b=i-k;

            for(l=b;l<i;++l)
            {
                if(x[l]>x[i]) ++db2;
                if(db2>0)
                    break;
            }
    }
    if(db1==0 && db2==0)
    {
        cout<<i+1;
        break;
    }
    }
    if(db2>0) cout<<-1;

    return 0;
}