#include <iostream>
#include <vector>
#include <string>
#include <stack>
#include <map>

int main()
{
    int N;
    std::string str;

    while(std::cin >>N)
    {
        std::vector<std::stack<int> > stacks;
        std::map <int,int> MapS;
        int count=0;

        for(int i=0;i<N;i++)
        {
        std::cin >>str;
        if(str=="PUSH")
        {
        int a,b,ind;
            std::cin >>a>>b;
            if(MapS.find(a)!=MapS.end())
            {
                ind = MapS[a];
            }
            else {
                std::pair<int,int> x;
                x.first = a;
                x.second = count++;
                MapS.insert(x);
                ind = x.second;
                stacks.push_back( std::stack<int>() );
            }

            stacks[ind].push(b);
        }
        else if(str == "POP")
        {
            int a,ind;
            std::cin >>a;

            if(MapS.find(a)!=MapS.end())
            {
                ind = MapS[a];
            }
            std::cout <<stacks[ind].top()<<std::endl;
            stacks[ind].pop();
        }
        }
    }
    return 0;
}