#!/usr/bin/env python3


def solve(x, y, z):
    if x > y:
        x, y = y, x
    d = min(y - x, z)
    x += d
    z -= d
    x += z // 2
    y += z // 2
    res = min(x, y)
    return res


def main():
    x, y, z = (int(z) for z in input().split())
    res = solve(x, y, z)
    print(res)


if __name__ == "__main__":
    main()