#include <iostream>
using namespace std;

int main()
{int i,q,db,s,t,b,a[200000],n,k;
    cin>>n>>k;
    for(i=0;i<n;i++){
        cin>>a[i];
    }
    b=-1;i=0;
    while(i<n && b==-1){q=i+k;t=1;
        if(i<k){s=1;
            while(s<=k && t==1){
                if(a[i]<a[i+s])t=0;
                s++;
        }
            while(s<=k-i && t==1){
                if(a[i]<a[i-s])t=0;
                s++;
        }
        }
        if(i>=k){s=1;
        while(s<=k && t==1){
            if(a[i]<a[i+s] || a[i]<a[i-s])t=0;
            s++;
        }
        }
        if(t==1)b=i+1;
        i++;
    }cout<<b;
    return 0;
}