import java.util.*;
import java.io.*;

public class Main{
    public static void main(String[] args){
        FastScanner fsc=new FastScanner();
        int n=fsc.nextInt(), k=fsc.nextInt();
        long x[]=new long[n], y[]=new long[n];
        for(int i=0;i<n;i++){
            x[i]=fsc.nextLong();
            y[i]=fsc.nextLong();
        }
        fsc.close();
        long ans=Long.MAX_VALUE;
        long xmin,xmax,ymin,ymax;
        int count=0;
        for(int x1=0;x1<n-1;x1++){
            for(int x2=x1+1;x2<n;x2++){
                for(int y1=0;y1<n-1;y1++){
                    for(int y2=y1+1;y2<n;y2++){
                        if(x[x1]>x[x2]){
                            xmax=x[x1];
                            xmin=x[x2];
                        }
                        else{
                            xmax=x[x2];
                            xmin=x[x1];
                        }
                        if(y[y1]>y[y2]){
                            ymax=y[y1];
                            ymin=y[y2];
                        }
                        else{
                            ymax=y[y2];
                            ymin=y[y1];
                        }
                        for(int i=0;i<n;i++) if(xmin<=x[i]&&x[i]<=xmax&&ymin<=y[i]&&y[i]<=ymax) count++;
                        if(count>=k) ans=Math.min(ans, (xmax-xmin)*(ymax-ymin));
                        count=0;
                    }
                }
            }
        }
        
        System.out.println(ans);
    }

    static class FastScanner {
        private final InputStream in = System.in;
        private final byte[] buffer = new byte[1024];
        private int ptr = 0;
        private int buflen = 0;
        private boolean hasNextByte() {
            if (ptr < buflen) {
                return true;
            }else{
                ptr = 0;
                try {
                    buflen = in.read(buffer);
                } catch (IOException e) {
                    e.printStackTrace();
                }
                if (buflen <= 0) {
                    return false;
                }
            }
            return true;
        }
        private int readByte() { if (hasNextByte()) return buffer[ptr++]; else return -1;}
        private static boolean isPrintableChar(int c) { return 33 <= c && c <= 126;}
        public boolean hasNext() { while(hasNextByte() && !isPrintableChar(buffer[ptr])) ptr++; return hasNextByte();}
        public String next() {
            if (!hasNext()) throw new NoSuchElementException();
            StringBuilder sb = new StringBuilder();
            int b = readByte();
            while(isPrintableChar(b)) {
                sb.appendCodePoint(b);
                b = readByte();
            }
            return sb.toString();
        }
        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' || '9' < b) {
                throw new NumberFormatException();
            }
            while(true){
                if ('0' <= b && b <= '9') {
                    n *= 10;
                    n += b - '0';
                }else if(b == -1 || !isPrintableChar(b)){
                    return minus ? -n : n;
                }else{
                    throw new NumberFormatException();
                }
                b = readByte();
            }
        }
        public int nextInt() {
            long nl = nextLong();
            if (nl < Integer.MIN_VALUE || nl > Integer.MAX_VALUE) throw new NumberFormatException();
            return (int) nl;
        }
        public double nextDouble() { return Double.parseDouble(next());}
        public void close(){
            try{in.close();}
            catch(IOException e){e.printStackTrace();}
        }
    }
}

Measured memory_bytes: 24276