type MinStack struct {
     stack []int
     mins []int
}


func Constructor() MinStack {
    return MinStack{
        stack: []int{},
        mins: []int{},
    }
}


func (this *MinStack) Push(val int)  {
    this.stack = append(this.stack, val)
    if len(this.mins) > 0 {
        this.mins = append(this.mins, min(this.mins[len(this.mins)-1],val))
    }else {
        this.mins = append(this.mins,val)
    }
}


func (this *MinStack) Pop()  {
    this.stack = this.stack[:len(this.stack)-1]
    this.mins = this.mins[:len(this.mins)-1]
}


func (this *MinStack) Top() int {
    return this.stack[len(this.stack)-1]
}


func (this *MinStack) GetMin() int {
    return this.mins[len(this.mins)-1]
}

func min(l,r int) int {
    if l > r {
        return r
    }
    return l
}


/**
 * Your MinStack object will be instantiated and called as such:
 * obj := Constructor();
 * obj.Push(val);
 * obj.Pop();
 * param_3 := obj.Top();
 * param_4 := obj.GetMin();
 */