Hi @WookGyeo and welcome to the forum!

Here’s your code formatted in a code block for readability:

# answer you want
a, b = input().split()
c = a + b
print(c)
does not give answer, only prints out a
a = input()

b = input()

c = a + b

print(c)

It can help to be a bit more explicit about what you actually want. Since I don’t know what your goal is, it’s hard to help you out. I can explain what the code does in both cases, so you’re hopefully able to determine for yourself what is going wrong.

• The first piece of code takes input from the command line, and uses split() to split up the input string. You can provide an argument to split to tell Python where to split the string on, but if you don’t (as you did here), it’ll split on any whitespace. By using a, b to unpack the resulting list, you tell Python to put the first item of the list into a and the second item of the list into b. Note this throws an error if your list is not exactly two items long (if I input test into your program, it’ll throw an error). Assuming no error was thrown, you then glue the two strings together and store that into c. Hence, if I input te st into the program, a will be te, b will be st and c will be test, which will be printed out.
• In the second program, you take two separate inputs. You then glue these together and print the result. If I input test the first time, then input ing the second time, a will be test, b will be ing, and c will be testing, which will be printed.