package main

import . "fmt"
import . "os"
import bf "bufio"

func main() {
	rd:=bf.NewReader(Stdin)
	wr:=bf.NewWriter(Stdout)
	var n int
	Fscan(rd,&n)
	t:=make([]int,n)
	s:=make([]string,n)
	for i:=range t {
		Fscan(rd,&t[i],&s[i])
	}
	for i:=range t {
		i=n-i-1
		if t[i]==1 {
			Fprint(wr,s[i])
		}
	}
	for i,c:=range t {
		if c==0 {
			Fprint(wr,s[i])
		}
	}
	Fprintln(wr)
	wr.Flush()
}