#include<bits/stdc++.h>
#include <atcoder/all>
#ifdef LOCAL
#include <debug_print.hpp>
#define debug(...) debug_print::multi_print(#__VA_ARGS__, __VA_ARGS__)
#else
#define debug(...) (static_cast<void>(0))
#endif
using namespace atcoder;
using mint=modint998244353;
using namespace std;
using ll=long long;
using ul=unsigned long long;
int dx[8] = {-1, 1, 0, 0, -1, -1, 1, 1};
int dy[8] = {0, 0, -1, 1, -1, 1, -1, 1};
using Graph=vector<vector<int>>;
ll op(ll a,ll b){return a+b;}
ll e(){return 0;}
int main(){
    int N,M;
    cin>>N>>M;
    vector<ll>A(N);
    for(int i=0;i<N;i++)cin>>A[i];
    sort(A.begin(),A.end());
    ll m=9e18,mm;
    for(int i=0;i<N-M+1;i++){
        if(m>A[i+M-1]-A[i])m=A[i+M-1]-A[i],mm=i;
    }
    ll sum=0;
    for(int i=mm;i<mm+M-1;i++){
        sum+=(A[i+1]-A[i])*(A[i+1]-A[i]);
    }
    cout<<sum<<endl;
}