Its so hard you can't even submit it

That's why you need to reach some good rating to propose a contest/problems...

As a person who have solved much more stupid harder problem, like the problem A in this contest https://codeforces.com/contest/1510, I don't think this problem is anything hard. My implementation in C++ is only under 100 lines.

The only complain about this problem is that you should state that the operation should have done in floating point arithmetic. Reading your note I thought that every operations are done in integer and that costs me about 10 submissions. I think your note should have been more complex to avoid confusion, like $$$2 / 3 * 5 \approx 3.333333$$$ but the answer should be 3.

I suggest you solve more problems first, improve your strength, and then propose problems...