Question

why we take input in any coding problem?​

Answer 1

Answer:

Data can be input in different ways: Written directly into the program. This is called hard coding. By the user when the program is running. From a file or other source when the program is running.

Answer 2

$\bf \huge \underline {\underline{ANSWER}}$

Input/output in interactive problems works much slower than in usual problems — try to use scanf/printf instead of cin/cout in С++, BufferedReader/PrintWriter in Java and etc.