Buggy python submission (verdict: Runtime Error):
sa = [s for s in input()]
sb = [s fir s in input()]
sc = [s for s in input()]

next_turn = "a"
flag = True

while flag:
    if next_turn == "a":
        if len(sa) == 0:
            print("A")
            flag = False
        else:
            next_turn = sa.pop(0)
    elif next_turn == "b":
        if len(sb) == 0:
            print("B")
            flag = False
        else:
            next_turn = sb.pop(0)
    elif next_turn == "c":
        if len(sc) ==0:
            print("C")
            flag = False
        else:
            next_turn = sc.pop(0)
        



Fixed submission:
sa = list(input())
sb = list(input())
sc = list(input())

turn = "a"

while True:
    if turn == "a":
        if len(sa) != 0:
            turn = sa.pop(0)
        else:
            print("A")
            exit()
    elif turn == "b":
        if len(sb) != 0:
            turn = sb.pop(0)
        else:
            print("B")
            exit()
    else:
        if len(sc) != 0:
            turn = sc.pop(0)
        else:
            print("C")
            exit()

Buggy python submission (verdict: Runtime Error):
sa = [s for s in input()]
sb = [s fir s in input()]
sc = [s for s in input()]

next_turn = "a"
flag = True

while flag:
    if next_turn == "a":
        if len(sa) == 0:
            print("A")
            flag = False
        else:
            next_turn = sa.pop(0)
    elif next_tunr == "b":
        if len(sb) == 0:
            print("B")
            flag = false
        else:
            next_turn = sb.pop(0)
    elif next_turn == "c":
        if len(sc) ==0:
            print("C")
            flag = False
        else:
            next_turn = sc.pop(0)
        



Fixed submission:
sa = list(input())
sb = list(input())
sc = list(input())

turn = "a"

while True:
    if turn == "a":
        if len(sa) != 0:
            turn = sa.pop(0)
        else:
            print("A")
            exit()
    elif turn == "b":
        if len(sb) != 0:
            turn = sb.pop(0)
        else:
            print("B")
            exit()
    else:
        if len(sc) != 0:
            turn = sc.pop(0)
        else:
            print("C")
            exit()

Buggy python submission (verdict: Runtime Error):
sa = list(input())
sb = list(input())
sc = list(input())

turn = "a"

while True:
    if turn == "a":
        if len(sa) != 0:
            turn = sa.pop(0)
        else:
            print("A")
            exit()
    elif turn == "b":
        if len(sb) != 0:
            turn = sb.pop(0)
        else:
            print("B")
            exit()
    else:
        if len(sc) != "c"
            turn = sc.pop(0)
        else:
            print("C")
            exit()





Fixed submission:
sa = list(input())
sb = list(input())
sc = list(input())

turn = "a"

while True:
    if turn == "a":
        if len(sa) != 0:
            turn = sa.pop(0)
        else:
            print("A")
            exit()
    elif turn == "b":
        if len(sb) != 0:
            turn = sb.pop(0)
        else:
            print("B")
            exit()
    else:
        if len(sc) != 0:
            turn = sc.pop(0)
        else:
            print("C")
            exit()