هیستوری

Main.py

q = int(input())
S = []
stack = [[]]

for i in range(q):
    A = list(input().split(" "))
    if A[0] == "insert":
        p = int(A[1])
        p -= 1
        SP = S.copy();
        SP.insert(p, A[2])
        stack.append(SP)
    elif A[0] == "delete":
        p = int(A[1])
        p -= 1
        SP = S.copy()
        SP.pop(p)
        stack.append(SP)
    else:
        stack.pop()
    S = stack[len(stack) - 1]
    #a, ab, cab, cb,

for ch in S:
    print(ch, end="")
print()