var assert = require('assert');

​

class MinStack {

  constructor() {}

​

  push(val) {}

​

  pop() {}

​

  peek() {}

​

  min() {}

}

​

try {

  var minstack = new MinStack();

  minstack.push(4);

  minstack.push(7);

  minstack.push(3);

  minstack.push(2);

  minstack.push(6);

  var min1 = minstack.min();

  minstack.pop();

  var min2 = minstack.min();

  minstack.pop();

  var min3 = minstack.min();

  minstack.pop();