Buggy python submission (verdict: Runtime Error):
def main():
    from sys import stdin
    #input = sys.stdin.readline
    sys.setrecursionlimit(10000000)
    from collections import Counter, deque
    #from collections import defaultdict
    from itertools import combinations, permutations
    #from itertools import accumulate, product
    from bisect import bisect_left,bisect_right
    from math import floor, ceil
    #from operator import itemgetter

    #mod = 1000000007

    S = input()
    Q = int(input())
    mae = ''
    usiro = ''
    s = True
    for _ in range(Q):
        q = stdin.readline()
        if q[0]=='1':
            s = not s
        else:
            if q[2]=='1' and s:
                mae = q[4] + mae
            elif q[2]=='2' and s:
                usiro = usiro + q[4] 
            elif q[2]=='2' and not s:
                mae = q[4] + mae
            else:
                usiro = usiro + q[4]
    if s:
        print(mae+S+usiro)
    else:
        print(usiro[::-1]+S[::-1]+mae[::-1])




if __name__ == '__main__':
    main()


Fixed submission:
def main():
    import sys
    #input = sys.stdin.readline
    sys.setrecursionlimit(10000000)
    from collections import Counter, deque
    #from collections import defaultdict
    from itertools import combinations, permutations
    #from itertools import accumulate, product
    from bisect import bisect_left,bisect_right
    from math import floor, ceil
    #from operator import itemgetter

    #mod = 1000000007

    S = input()
    Q = int(input())
    mae = ''
    usiro = ''
    s = True
    for _ in range(Q):
        q = list(input().split())
        if q[0]=='1':
            s = not s
        else:
            if q[1]=='1' and s:
                mae = q[2] + mae
            elif q[1]=='2' and s:
                usiro = usiro + q[2] 
            elif q[1]=='2' and not s:
                mae = q[2] + mae
            else:
                usiro = usiro + q[2]
    if s:
        print(mae+S+usiro)
    else:
        print(usiro[::-1]+S[::-1]+mae[::-1])




if __name__ == '__main__':
    main()

Buggy python submission (verdict: Runtime Error):
def main():
    from sys import stdin
    #input = sys.stdin.readline
    sys.setrecursionlimit(10000000)
    from collections import Counter, deque
    #from collections import defaultdict
    from itertools import combinations, permutations
    #from itertools import accumulate, product
    from bisect import bisect_left,bisect_right
    from math import floor, ceil
    #from operator import itemgetter

    #mod = 1000000007

    S = input()
    Q = int(input())
    mae = ''
    usiro = ''
    s = True
    for _ in range(Q):
        q = stdin.readline()
        if q[0]=='1':
            s = not s
        else:
            if q[1]=='1' and s:
                mae = q[2] + mae
            elif q[1]=='2' and s:
                usiro = usiro + q[2] 
            elif q[1]=='2' and not s:
                mae = q[2] + mae
            else:
                usiro = usiro + q[2]
    if s:
        print(mae+S+usiro)
    else:
        print(usiro[::-1]+S[::-1]+mae[::-1])




if __name__ == '__main__':
    main()


Fixed submission:
def main():
    import sys
    #input = sys.stdin.readline
    sys.setrecursionlimit(10000000)
    from collections import Counter, deque
    #from collections import defaultdict
    from itertools import combinations, permutations
    #from itertools import accumulate, product
    from bisect import bisect_left,bisect_right
    from math import floor, ceil
    #from operator import itemgetter

    #mod = 1000000007

    S = input()
    Q = int(input())
    mae = ''
    usiro = ''
    s = True
    for _ in range(Q):
        q = list(input().split())
        if q[0]=='1':
            s = not s
        else:
            if q[1]=='1' and s:
                mae = q[2] + mae
            elif q[1]=='2' and s:
                usiro = usiro + q[2] 
            elif q[1]=='2' and not s:
                mae = q[2] + mae
            else:
                usiro = usiro + q[2]
    if s:
        print(mae+S+usiro)
    else:
        print(usiro[::-1]+S[::-1]+mae[::-1])




if __name__ == '__main__':
    main()