#include <bits/stdc++.h>
#define ios ios::sync_with_stdio(0); cin.tie(NULL); cout.tie(NULL)
#define pb push_back
#define mp make_pair
#define fi first
#define se second
#define enter cout << '\n'

using namespace std;

typedef long long ll;
typedef pair <int, int> pii;
typedef pair <ll, ll> pll;
typedef vector <int> vi;
typedef vector <pii> vii;
typedef vector <ll> vl;
typedef vector <pll> vll;
typedef queue <int> qi;
typedef queue <pii> qii;
typedef queue <ll> ql;
typedef queue <pll> qll;

const int INF = 0x3f3f3f3f;
const int MOD = 1e9 + 9;
const double EPSILON = 1e-10;
const int NMAX = 16e3 + 5;
const int MMAX = 1e4 + 5;
const int DX[] = {0, 0, 1, -1};
const int DY[] = {1, -1, 0, 0};

ifstream fin("banana.in");
ofstream fout("banana.out");

int n, k;
int root[NMAX], rang[NMAX];
int m[MMAX][MMAX];

int find_root(int x)
{
    int i, aux;

    for (i = x; root[i] != i; i = root[i]);

    while (root[x] != x)
    {
        aux = root[x];
        root[x] = i;
        x = aux;
    }
    return i;
}

void unite(int x, int y)
{
    x = find_root(x);
    y = find_root(y);

    if (x == y) return;

    root[y] = x;
    rang[x] += rang[y];
    rang[y] = 0;
}

int main()
{
    fin >> n >> k;
    for (int i = 1; i <= n; ++i)
    {
        int x, y, xn, yn;
        fin >> x >> y;
        m[x][y] = i;

        root[i] = i;
        rang[i] = 1;

        for (int dir = 0; dir < 4; ++dir)
        {
            xn = x + DX[dir];
            yn = y + DY[dir];
            if (m[xn][yn])
                unite(m[xn][yn], i);
        }
    }

    sort(rang + 1, rang + n + 1, greater<int>());

    int ans = 0;
    for (int i = 1; i <= k; ++i)
        ans += rang[i];

    fout << ans;

    return 0;
}