This look like a challenge, in this kind of challenges, the goal is to test your skills. So your answer is that you are unable to solve the problem.

**In this kind of problem, just like with homework, the first step is to find the logic, the mathematics.**

So take a sheet of paper and a pencil and solve the samples by hand. When you got it, start writing the program.
We do not do your HomeWork.

HomeWork is not set to test your skills at begging other people to do your work, it is set to make you think and to help your teacher to check your understanding of the courses you have taken and also the problems you have at applying them.

Any failure of you will help your teacher spot your weaknesses and set remedial actions.

Any failure of you will help you to learn what works and what don't, it is called 'trial and error' learning.

So, give it a try, reread your lessons and start working. If you are stuck on a specific problem, show your code and explain this exact problem, we might help.

As programmer,

**your job is to create algorithms** that solve specific problems and you can't rely on someone else to eternally do it for you, so there is a time where you will have to learn how to. And the sooner, the better.

When you just ask for the solution, it is like trying to learn to drive a car by having someone else training.

Creating an algorithm is basically finding the maths and make necessary adaptation to fit your actual problem.

[Update]

The code in your question is not even remotely related to the statement.

Quote:

can anyone explain how output comes??

That is the core of the contest, they want to know if you can workout the math. So if we just give you the answer it is sheeting.

The principle of problem solving is :

First step: take a sheet of paper and a pencil

Second step: solve the problem by hand, find the maths or algorithm

Third step: your program is automating the solution you found.