#include<iostream>
#include<fstream>
#include<climits>
#include<cmath>
#include<algorithm>

using namespace std;

struct point
{
    int x;
    int y;
};

struct dist
{
    int a; //point number
    int d;
};

int distance1 (point A, point B)
{
    return sqrt(abs(A.x-B.x)*abs(A.x-B.x) + abs(A.y-B.y)*abs(A.y-B.y));
}

bool operator <(dist A, dist B)
{
    if(A.d<B.d) return true;

    return false;
}

point start;
dist distances[100005];

int main()
{
    ifstream input("ring.in");
    ofstream output("ring.out");

    int n,k;
    point a[100005];

    int n_copy;
    long long r_small, r_huge;

    long long answer = 99999999999;

    input >> n >> k;
    for(int i = 0;i<n;i++)
        input >> a[i].x >> a[i].y;


    start.x = 0;
    start.y = 0;
    for(int i = 0;i<n;i++)
    {
        distances[i].d = distance1(start,a[i]);
        distances[i].a = i;
    }
    sort(distances,distances+n);

    for(n_copy = k + 1;n_copy<=n;n_copy++)
    {
        r_huge = distances[n_copy-1].d;

        if(distances[n_copy-k].d==distances[n_copy-k-1].d) continue;
        r_small = distances[n_copy-k].d - 1;

        if(r_huge*r_huge - r_small*r_small<answer) answer = r_huge*r_huge - r_small*r_small;
    }

    output << answer << endl;
}