class Solution:
    def formatList(self , head ):
        if not head:
            return head
        index=head
        head=head.next
        i=index
        flag=0
        while head:
            if flag==0:
                i.next=head
                i=i.next
                head=head.next
                flag=1
            else:
                a=head
                head=head.next
                a.next=index
                index=a
                flag=0
        return index

class Solution:
    def sortList(self , head ):
        dic={}
        while head:
            if head.val in dic:
                dic[head.val]+=1
            else:
                dic[head.val]=1
            head=head.next
        a=sorted(dic.items())
        k=[]
        for ass in a:
            k.append([ass[0],ass[1]])
        res=ListNode(0)
        now=res
        num=max(dic.values())
        for i in range(num):
            for item in k:
                if item[1]>0:
                    now.next=ListNode(item[0])
                    now=now.next
                    item[1]=item[1]-1
        return res.next

num = int(input())
data = []
for i in range(num):
    a = input().split()
    if 'in' == a[0]:
        data.append([int(a[1]), a[2]])
    else:
        if not data:
            print(-1)
            continue
        else:
            a[1]=int(a[1])
            if a[1]==0:
                print(data.pop(0)[1])
                continue
            else:
                flag=0
                for item in data:
                    if a[1]==int(item[0]):
                        print(item[1])
                        data.remove(item)
                        flag=1
                        break
                if flag==0:
                    print(-1)