#light "off"
open System;;
open System.IO;;

let reader = new StreamReader(new BufferedStream(Console.OpenStandardInput ()))
let writer = new StreamWriter(new BufferedStream(Console.OpenStandardOutput ()))

let skipSpaces () = while reader.Peek () <= int ' ' do reader.Read () |> ignore done;;
let read f = skipSpaces (); [|while reader.Peek () > int ' ' do yield char (reader.Read ()) done |] |> System.String |> f;;
let readint () = skipSpaces (); let mutable ans = 0 in while reader.Peek () > int ' ' do ans <- ans * 10 + (reader.Read () - int '0'); done; ans;;
let write (s : string) = writer.Write s;;
let writeln (s : string) = writer.WriteLine s;;


let a, b, c = readint (), readint (), readint();;
c - min (a - b) c |> printfn "%d";;


reader.Close();;
writer.Close();;