import sys
readline=sys.stdin.readline
write=sys.stdout.write
from math import gcd as GCD
import math

N=int(readline())
L,R=[],[]
for _ in range(N):
    T,S=readline().split()
    T=int(T)
    if T:
        L.append(S)
    else:
        R.append(S)
print(*L[::-1]+R,sep="")