/* AtCoder My Practice
 * author: Leonardone @ NEETSDKASU
 */   /* ABC075 D 解説読後 */
const UNI = 100000;
class Int {
  num = [0, 0, 0, 0];
  minus = false;
  setValue(v: number): Int {
    if (v < 0) {
      this.minus = true;
      v = -v;
    }
    for (let i = 0; i < 4; i++) {
      this.num[i] = v % UNI;
      v = (v / UNI) | 0;
    }
    return this;
  }
  less(that: Int): Boolean {
    if (this.minus !== that.minus) {
      return this.minus;
    }
    for (let i = 3; i >= 0; i--) {
      if (this.num[i] < that.num[i]) {
        return !this.minus;
      } else if (this.num[i] > that.num[i]) {
        return this.minus;
      }
    }
    return false;
  }
  add(that: Int): Int {
    if (this.minus !== that.minus) {
      this.minus = !this.minus;
      const less = this.less(that) === this.minus;
      let ret = less ? this.sub(that) : that.sub(this);
      ret.minus = less !== this.minus;
      this.minus = !this.minus;
      return ret;
    }
    let ret = new Int();
    let car = 0;
    ret.minus = this.minus;
    for (let i = 0; i < 4; i++) {
      ret.num[i] = this.num[i] + that.num[i] + car;
      car = (ret.num[i] / UNI) | 0;
      ret.num[i] %= UNI;
    }
    return ret;
  }
  sub(that: Int): Int {
    if (this.minus !== that.minus) {
      that.minus = !that.minus;
      let ret = this.add(that);
      that.minus = !that.minus;
      return ret;
    }
    let ret = new Int();
    let car = 0;
    let less = this.less(that) !== this.minus;
    let [x, y] = less ? [that, this] : [this, that];
    ret.minus = less !== this.minus;
    for (let i = 0; i < 4; i++) {
      ret.num[i] = x.num[i] - y.num[i] - car;
      if (ret.num[i] < 0){
        car = 1;
        ret.num[i] += UNI;
      } else {
        car = 0;
      }
    }
    return ret;
  }
  mul(that: Int): Int {
    let ret = new Int();
    let car = 0;
    ret.minus = this.minus !== that.minus;
    for (let i = 0; i < 4; i++) {
      ret.num[i] += car;
      for (let j = 0; j < 4; j++) {
        ret.num[i+j] += this.num[i] * that.num[j];
      }
      car = (ret.num[i] / UNI) | 0;
      ret.num[i] %= UNI;
    }
    return ret;
  }
  toString(): string {
    let s = '';
    for (let i = 3; i >= 0; i--) {
      if (s.length === 0) {
        if (this.num[i] > 0) {
          s = this.minus ? '-' : '';
          s += this.num[i].toString();
        }
      } else {
        const n = (UNI + this.num[i]).toString();
        s += n.substring(1);
      }
    }
    return s.length === 0 ? '0' : s;
  }
}
let buf = '';
process.stdin.setEncoding('utf8');
process.stdin.on('readable', () => {
  let s = process.stdin.read();
  if (s !== null) { buf += s.toString(); }
});
process.stdin.on('end', () => {
  const lines = buf.trim().split("\n");
  const getVals = (p) => lines[p].split(' ').map( (x) => parseInt(x) )
  const [n, k] = getVals(0);
  let rects: {x: number, y: number}[] = [];
  for (let i = 0; i < n; i++) {
    const [x, y] = getVals(i+1);
    rects[i] = {x, y};
  }
  let ans: Int | null = null;
  for (let i1 = 0; i1 < n; i1++) {
    for (let i2 = i1+1; i2 < n; i2++) {
      let y1 = rects[i1].y;
      let y2 = rects[i2].y;
      if (y1 === y2) { continue; }
      if (y2 < y1) {
        [y1, y2] = [y2, y1];
      }
      for (let j1 = 0; j1 < n; j1++) {
        for (let j2 = j1+1; j2 < n; j2++) {
	      let x1 = rects[j1].x;
          let x2 = rects[j2].x;
          if (x1 === x2) { continue; }
          if (x2 < x1) {
            [x1, x2] = [x2, x1];
          }
          let cnt = 0;
          for (let p = 0; p < n; p++) {
            const r = rects[p];
            if (r.x < x1 || x2 < r.x) { continue; }
            if (r.y < y1 || y2 < r.y) { continue; }
            cnt++;
          }
          if (cnt >= k) {
            const Y1 = (new Int()).setValue(y1);
            const Y2 = (new Int()).setValue(y2);
            const X1 = (new Int()).setValue(x1);
            const X2 = (new Int()).setValue(x2);
            const s = Y2.sub(Y1).mul(X2.sub(X1));
            if (ans === null || s.less(ans)) {
              ans = s;
            } 
          }
        } // j2
      } // j1
    } // i2
  } // i1
  console.log(ans.toString());
});

Measured memory_bytes: 11432