l = input().split(' ')

X = int(l[0])
Y = int(l[1])
Z = int(l[2])
MIN = min([X, Y])
MAX = max([X, Y])
i = MIN
while i < MAX:
    if Z == 0:
        break
    i = i + 1
    Z = Z - 1
print(i + int(Z / 2))