#include<iostream>
#include<algorithm>
#include<vector>
#define ll long long
using namespace std;

bool place(vector<ll> a, ll start, ll end, ll mid, ll c){

    if(c == 1)
        return true;
    if(c > (end - start + 1))
    {
        return false;
    }
    ll cow = 1;//assume one cow is placed at position 0;
    ll i = 0;
    while(cow <= c){
        //   cout<<start<< " "<<end<<endl;
        // cout<<start;
         cout<<" "<<start<< "*"<<i<<endl;
        for( i = start + 1; i <= end; i++ ){
            if((a[i] - a[start]) >= mid){
                cow++;

                //another cow positioned at index i;
                 start = i;
                cout<<" "<<start<< "*"<<i<<endl;
                // cout<<a[i]<<" "<<a[start]<<" "<<i<<endl;
                break;
            }
        }

        if(i >= end && cow <c)
            return false;
        else
            return true;

    }


    return true;
}

int main() {
   ll n, c;
   cin>>n>>c;
   vector<ll> a(n);

   for(ll i = 0; i < n; i++){
       cin>>a[i];

   }

   ll start = 0, end = n - 1, ans = 0;
    sort(a.begin(), a.end());
//      for(ll i = 0; i < n; i++){
//       cout<<a[i]<<" "<<"*"<<endl;
//   }
    while(start <= end){
        ll mid = (start + end)/2;
        if(place (a, 0, n -1, mid, c)){
            ans = mid;
            start = mid + 1;
        }
        else{
            end = mid - 1;
        }
    }
  //  cout<<ans<<endl;
    return 0;
}