func readInts() -> [Int] {
    return readLine()!.split(separator: " ").map { Int($0)! }
}

func main() {
    let abc = readInts()
    
    if abc[2] + abc[1] - abc[0] >= 0 {
        print(abc[2] + abc[1] - abc[0])
    } else {
        print("0")
    }
}

main()
