func readInts() -> [Int] {
    return readLine()!.split(separator: " ").map { Int($0)! }
}
let mizu = readInts()
let a = mizu[0]
let b = mizu[1]
let c = mizu[2]
let anogoukei = b + c - a
if anogoukei>0 {
  print(anogoukei)
} else { 
  print(0)
}