Solving HackerRank's Functional Challenges in F#: Solve Me First FP

Couple of years ago I had a good time practicing Go by solving a number of programming challenges on Hackerrank. This time I will try solve functional challenges using F#.

There is the first one:

Your task is to scan two numbers, A and B from STDIN, and print the sum A+B on STDOUT.

It is just a basic challenge to get convenient with solution submision and language basics. The code looks pretty much C#:

open System

let main argv = 
    let a = Console.ReadLine() |> int
    let b = int(Console.ReadLine())
    printfn "%d" (a+b)
    0 // return an integer exit code

Console.ReadLine() |> int and int(Console.ReadLine()) are equivalent forms. a |> b is just b(a).