package main

import (
	"bufio"
	"fmt"
	"os"
	"strconv"
	"strings"
)

/*
1: push 5;push 2;push 1;push 3;push 0;min;top;pop;pop;pop;pop
2:
*/
func main() {
	var minStack = Constructor()
	input := bufio.NewScanner(os.Stdin)
	for input.Scan() {
		line := input.Text()
		if strings.HasPrefix(line, "push ") {
			var digitStr = line[5:]
			var digit, _ = strconv.Atoi(digitStr)
			minStack.Push(digit)
			continue
		}

		if strings.HasPrefix(line, "pop") {
			minStack.Pop()
		}

		if strings.HasPrefix(line, "min") {
			fmt.Println(minStack.Min())
		}

		if strings.HasPrefix(line, "top") {
			fmt.Println(minStack.Top())
		}

		fmt.Println(minStack.Stack1, "--------", minStack.Stack2)
	}
}

type MinStack struct {
	Stack1 []int
	Stack2 []int
}

/** initialize your data structure here. */
func Constructor() MinStack {
	return MinStack{}
}

func (this *MinStack) Push(x int) {
	this.Stack1 = append(this.Stack1, x)
	var length = len(this.Stack2)
	if length == 0 {
		this.Stack2 = append(this.Stack2, x)
		return
	}
	if this.Stack2[length-1] >= x {
		this.Stack2 = append(this.Stack2, x)
	}
}

func (this *MinStack) Pop() {
	var length = len(this.Stack1)
	if length == 0 {
		return
	}

	var value = this.Stack1[length-1]
	this.Stack1 = this.Stack1[0 : length-1]

	var stack2Length = len(this.Stack2)
	if this.Stack2[stack2Length-1] == value {
		this.Stack2 = this.Stack2[0 : stack2Length-1]
	}
}

func (this *MinStack) Top() int {
	var length = len(this.Stack1)
	if length == 0 {
		return -1
	}

	return this.Stack1[length-1]
}

func (this *MinStack) Min() int {
	var length = len(this.Stack2)
	if length == 0 {
		return -1
	}
	return this.Stack2[length-1]
}