import java.io.OutputStream;
import java.io.IOException;
import java.io.InputStream;
import java.io.OutputStream;
import java.io.PrintWriter;
import java.io.BufferedWriter;
import java.util.InputMismatchException;
import java.io.IOException;
import java.util.TreeSet;
import java.util.ArrayList;
import java.util.List;
import java.io.Writer;
import java.io.OutputStreamWriter;
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;
        InputReader in = new InputReader(inputStream);
        OutputWriter out = new OutputWriter(outputStream);
        TaskD solver = new TaskD();
        solver.solve(1, in, out);
        out.close();
    }

    static class TaskD {
        public void solve(int testNumber, InputReader in, OutputWriter out) {
            int n = in.readInt();
            int k = in.readInt();

            int[] x = new int[n];
            int[] y = new int[n];
            for (int i = 0; i < n; i++) {
                x[i] = in.readInt();
                y[i] = in.readInt();
            }

            TreeSet<Integer> setX = new TreeSet<>();
            TreeSet<Integer> setY = new TreeSet<>();
            for (int i = 0; i < n; i++) {
                setX.add(x[i]);
                setY.add(y[i]);
            }

            long ans = Long.MAX_VALUE;
            List<Integer> listX = new ArrayList<>(setX);
            List<Integer> listY = new ArrayList<>(setY);
            for (int i = 0; i < listX.size(); i++) {
                for (int j = i + 1; j < listX.size(); j++) {
                    for (int l = 0; l < listY.size(); l++) {
                        for (int m = l + 1; m < listY.size(); m++) {
                            int count = 0;
                            for (int o = 0; o < n; o++) {
                                if (listX.get(i) <= x[o] && x[o] <= listX.get(j)
                                        && listY.get(l) <= y[o] && y[o] <= listY.get(m)) {
                                    count++;
                                }
                            }
                            if (count >= k) {
                                long xx = listX.get(j) - listX.get(i);
                                long yy = listY.get(m) - listY.get(l);
                                ans = Math.min(ans, xx * yy);
                            }
                        }
                    }
                }
            }

            out.printLine(ans);
        }

    }

    static class OutputWriter {
        private final PrintWriter writer;

        public OutputWriter(OutputStream outputStream) {
            writer = new PrintWriter(new BufferedWriter(new OutputStreamWriter(outputStream)));
        }

        public OutputWriter(Writer writer) {
            this.writer = new PrintWriter(writer);
        }

        public void close() {
            writer.close();
        }

        public void printLine(long i) {
            writer.println(i);
        }

    }

    static class InputReader {
        private InputStream stream;
        private byte[] buf = new byte[1024];
        private int curChar;
        private int numChars;
        private InputReader.SpaceCharFilter filter;

        public InputReader(InputStream stream) {
            this.stream = stream;
        }

        public int read() {
            if (numChars == -1) {
                throw new InputMismatchException();
            }
            if (curChar >= numChars) {
                curChar = 0;
                try {
                    numChars = stream.read(buf);
                } catch (IOException e) {
                    throw new InputMismatchException();
                }
                if (numChars <= 0) {
                    return -1;
                }
            }
            return buf[curChar++];
        }

        public int readInt() {
            int c = read();
            while (isSpaceChar(c)) {
                c = read();
            }
            int sgn = 1;
            if (c == '-') {
                sgn = -1;
                c = read();
            }
            int res = 0;
            do {
                if (c < '0' || c > '9') {
                    throw new InputMismatchException();
                }
                res *= 10;
                res += c - '0';
                c = read();
            } while (!isSpaceChar(c));
            return res * sgn;
        }

        public boolean isSpaceChar(int c) {
            if (filter != null) {
                return filter.isSpaceChar(c);
            }
            return isWhitespace(c);
        }

        public static boolean isWhitespace(int c) {
            return c == ' ' || c == '\n' || c == '\r' || c == '\t' || c == -1;
        }

        public interface SpaceCharFilter {
            public boolean isSpaceChar(int ch);

        }

    }
}



Measured memory_bytes: 23384