Revise paste Activation Keys

first_line = input()

while True:
    line = input()
    if line == "Generate":
        break

line_split = line.split(">>>")
    command = line_split[0]

if command == "Contains":
        substring = line_split[1]
        if substring in first_line:
            print(f"{first_line} contains {substring}")
        else:
            print(f"Substring not found!")

elif command == "Flip":
        current_command = line_split[1]
        start_idx = int(line_split[2])
        end_idx = int(line_split[3])
        if current_command == "Upper":
            first_part = (first_line[:start_idx])
            middle_part = (first_line[start_idx:end_idx]).upper()
            second_part = (first_line[end_idx:])
            first_line = first_part + middle_part + second_part
            print(first_line)
        else:
            first_part = (first_line[:start_idx])
            middle_part = (first_line[start_idx:end_idx]).lower()
            second_part = (first_line[end_idx:])
            first_line = first_part + middle_part + second_part
            print(first_line)

elif command == "Slice":
        start_idx = int(line_split[1])
        end_idx = int(line_split[2])
        first_part = (first_line[:start_idx])
        second_part = (first_line[end_idx:])
        first_line = first_part + second_part
        print(first_line)

print(f"Your activation key is: {first_line}")