Problem:
Score : 100 points

Problem Statement

We have two bottles for holding water.

Bottle 1 can hold up to A milliliters of water, and now it contains B milliliters of water.

Bottle 2 contains C milliliters of water.

We will transfer water from Bottle 2 to Bottle 1 as much as possible.

How much amount of water will remain in Bottle 2?

Constraints

All values in input are integers.

1 \leq B \leq A \leq 20

1 \leq C \leq 20

Input

Input is given from Standard Input in the following format:

A B C

Output

Print the integer representing the amount of water, in milliliters, that will remain in Bottle 2.

Sample Input 1

6 4 3

Sample Output 1

1

We will transfer two milliliters of water from Bottle 2 to Bottle 1, and one milliliter of water will remain in Bottle 2.

Sample Input 2

8 3 9

Sample Output 2

4

Sample Input 3

12 3 7

Sample Output 3

0

Solution in Go (1.6) (judge verdict: Accepted)

package main

import (
	"bufio"
	"fmt"
	"log"
	"math"
	"os"
	"strconv"
)

// ----------------------------------------------------------------

func main() {
	var a int
	var b int
	var c int
	fmt.Scan(&a, &b, &c)

	if a-b >= c {
		fmt.Println(0)
	} else {
		fmt.Println(c - a + b)
	}
}

// ----------------------------------------------------------------

var dx = []int{0, 1, 0, -1, 0}
var dy = []int{1, 0, -1, 0, 0}
var inf = int(1e9)

func pow(a, b int) int {
	return int(math.Pow(float64(a), float64(b)))
}

func lcm(a, b int) int {
	return a * b / gcd(a, b)
}

func gcd(a, b int) int {
	if a < b {
		a, b = b, a
	}
	for b != 0 {
		a, b = b, a%b
	}
	return a
}

func max(a ...int) int {
	r := a[0]
	for i := 0; i < len(a); i++ {
		if r < a[i] {
			r = a[i]
		}
	}
	return r
}

func min(a ...int) int {
	r := a[0]
	for i := 0; i < len(a); i++ {
		if r > a[i] {
			r = a[i]
		}
	}
	return r
}

func sum(a []int) (r int) {
	for i := range a {
		r += a[i]
	}
	return r
}

func abs(a int) int {
	if a < 0 {
		return -a
	}
	return a
}

type pair struct {
	a, b int
}

type pairs []pair

func (p pairs) Len() int {
	return len(p)
}

func (p pairs) Swap(i, j int) {
	p[i], p[j] = p[j], p[i]
}

func (p pairs) Less(i, j int) bool {
	if p[i].a == p[j].a {
		return p[i].b < p[j].b
	}
	return p[i].a < p[j].a
}

var nextReader func() []byte

func init() {
	nextReader = newScanner()
	log.SetFlags(log.Lshortfile)
}

func newScanner() func() []byte {
	r := bufio.NewScanner(os.Stdin)
	r.Buffer(make([]byte, 1024), int(1e+11))
	r.Split(bufio.ScanWords)
	return func() []byte {
		r.Scan()
		return r.Bytes()
	}
}

func nextBytes() []byte {
	return nextReader()
}

func nextString() string {
	return string(nextReader())
}

func nextInt64() int64 {
	v, _ := strconv.ParseInt(string(nextReader()), 10, 64)
	return v
}

func nextInt() int {
	v, _ := strconv.Atoi(string(nextReader()))
	return v
}

func nextInts(n int) []int {
	r := make([]int, n)
	for i := 0; i < n; i++ {
		r[i] = nextInt()
	}
	return r
}

func nextFloat64() float64 {
	f, _ := strconv.ParseFloat(string(nextReader()), 64)
	return f
}