x, y, z = map(int, input().split())

while True:
    if x < y:
        x += 1
        z -= 1
        if z == 0:
            print(min(x, y))
            break
    elif x > y:
        y += 1
        z -= 1
        if z == 0:
            print(min(x, y))
            break
    else:
        x += 1
        z -= 1
        if z == 0:
            print(min(x, y))
            break
        y += 1
        z -= 1
        if z == 0:
            print(min(x, y))
            break