import java.io.OutputStream;
import java.io.IOException;
import java.io.InputStream;
import java.io.PrintWriter;
import java.util.Arrays;
import java.io.IOException;
import java.util.NoSuchElementException;
import java.io.InputStream;

/**
 * Built using CHelper plug-in
 * Actual solution is at the top
 */
public class Main {
    public static void main(String[] args) {
        InputStream inputStream = System.in;
        OutputStream outputStream = System.out;
        FasterScanner in = new FasterScanner(inputStream);
        PrintWriter out = new PrintWriter(outputStream);
        TaskD solver = new TaskD();
        solver.solve(1, in, out);
        out.close();
    }

    static class TaskD {
        public void solve(int testNumber, FasterScanner in, PrintWriter out) {
            final int n = in.nextInt();
            final int k = in.nextInt();

            long[] x = new long[n];
            long[] y = new long[n];
            long[][] p = new long[2][n];
            for (int i = 0; i < n; i++) {
                x[i] = in.nextLong();
                y[i] = in.nextLong();
                p[0][i] = x[i];
                p[1][i] = y[i];
            }
            Arrays.sort(x);
            Arrays.sort(y);

            long ans = Long.MAX_VALUE;
            for (int xi = 0; xi < n; xi++) {
                for (int xj = xi + 1; xj < n; xj++) {
                    for (int yi = 0; yi < n; yi++) {
                        for (int yj = yi + 1; yj < n; yj++) {
                            long xl = x[xi];
                            long xr = x[xj];
                            long yu = y[yi];
                            long yd = y[yj];
                            int count = 0;
                            for (int m = 0; m < n; m++) {
                                long cx = p[0][m];
                                long cy = p[1][m];
                                if (cx >= xl && cx <= xr && cy >= yu && cy <= yd) count++;
                            }
                            if (count >= k) ans = Math.min(ans, (xr - xl) * (yd - yu));
                        }
                    }
                }
            }

            out.println(ans);
        }

    }

    static class FasterScanner {
        private InputStream in;
        private byte[] buffer;
        private int bufPointer;
        private int bufLength;

        public FasterScanner(InputStream in) {
            this.in = in;
            buffer = new byte[1024];
        }

        private boolean hasNextByte() {
            if (bufPointer < bufLength) return true;
            bufPointer = 0;
            try {
                bufLength = in.read(buffer);
            } catch (IOException e) {
                e.printStackTrace();
            }
            return (bufLength > 0);
        }

        private int readByte() {
            if (hasNextByte()) return buffer[bufPointer++];
            return -1;
        }

        private static boolean isPrintableChar(int c) {
            return (c >= 33 && c <= 126);
        }

        public boolean hasNext() {
            while (hasNextByte() && !isPrintableChar(buffer[bufPointer])) bufPointer++;
            return hasNextByte();
        }

        public int nextInt() {
            long nl = nextLong();
            if (nl < Integer.MIN_VALUE || nl > Integer.MAX_VALUE) throw new NumberFormatException();
            return (int) nl;
        }

        public long nextLong() {
            if (!hasNext()) throw new NoSuchElementException();
            long n = 0;
            boolean minus = false;
            int b = readByte();
            if (b == '-') {
                minus = true;
                b = readByte();
            }
            if (b < '0' || b > '9') throw new NumberFormatException();

            while (true) {
                if (b >= '0' && b <= '9') {
                    n *= 10;
                    n += b - '0';
                } else if (b == -1 || !isPrintableChar(b)) {
                    return minus ? -n : n;
                } else {
                    throw new NumberFormatException();
                }
                b = readByte();
            }
        }

    }
}



Measured memory_bytes: 22484