let rec count n x y z = 
    if n = z && n <> x && n <> y then 1 else if n = z then 0 
    else if n = x || n = y then 0 + count (n+1) x y z else 1 + count (n+1) x y z 
let () =
    let x, y, z = Scanf.scanf "%d %d %d\n" (fun x y z -> x, y, z) in
    Printf.printf "%d\n" (count 1 x y z)