// No.920 あかあお
package main

import (
	"fmt"
	"math"
)

func main() {
	var x, y, z int
	fmt.Scan(&x, &y, &z)
	var diff = int(math.Abs(float64(x) - float64(y)))
	if z == 0 {
		fmt.Println(min(x, y))
	} else if diff >= z {
		fmt.Println(min(x, y) + min(diff, z))
	} else {
		fmt.Println(min(x, y) + diff + int((z-diff)/2))
	}
}