import math
import sys
def S(): return sys.stdin.readline().rstrip()
def I(): return int(sys.stdin.readline().rstrip())
def MI(): return map(int, sys.stdin.readline().rstrip().split())
def LI(): return list(map(int, sys.stdin.readline().rstrip().split()))
def LS(): return list(sys.stdin.readline().rstrip().split())

n = I()
f = []
b = []
for i in range(n):
    x = LS()
    if x[0] == '0':
        b.append(x[1])
    else:
        f.append(x[1])

ans = "".join(f[::-1]+b)
print(ans)