def main():
    n = int(input())
    l = [input().split() for _ in range(n)]
    ans = ['' for _ in range(n)]
    cur0, cur1 = n-1, 0
    for t, s in l[::-1]:
        if t == '0':
            ans[cur0] = s
            cur0 -= 1
        elif t == '1':
            ans[cur1] = s
            cur1 += 1
    print(''.join(ans))


if __name__ == '__main__':
    main()