Untitled

#include <bits/stdc++.h>
using namespace std ;
#define int long long 
#define For(n) for(int i = 0; i < n; i++)
#define endl '\n'
#define ld long double
int n,k;
bool can (ld arr[],ld mid,int n,int k){
    priority_queue<ld,vector<ld>>pq;
    For(n)pq.push(arr[i]);
    while (k--&&!pq.empty())
    {
        ld tmp = pq.top();pq.pop();
        pq.push(tmp-mid);pq.push(mid);
    }
    // cout << mid << ' '<< pq.top()<<endl;
    return pq.top() <= mid;
}
void solve (){  
    int n,k;cin>>n>>k;
    ld arr[n];
    For(n)cin>>arr[i];
    sort(arr,arr+n);
    ld l =1,r=arr[n-1];
    ld ans = arr[n-1];
    int cnt = 10e3;
    while (l<=r&&cnt--){
        ld mid = (r+l)/2;
        if(can(arr,mid,n,k)){
            ans = mid;
            r=mid;
        } 
        else l =mid;
    }
    cout << round(ans) << endl;
}
signed main ()
{
ios_base::sync_with_stdio(0);cin.tie(0);cout.tie(0);    
int t =1;
// cin>>t;
while (t--){
    solve();
}    
}