<reponame>banerjeesoumya15/Learn-By-Write
# put your python code here
g1_ = abs(int(input()))
g2_ = abs(int(input()))
g3_ = abs(int(input()))
desk1 = g1_ // 2 
desk1_ = g1_ % 2
desk2 = g2_ // 2 
desk2_ = g2_ % 2
desk3 = g3_ // 2 
desk3_ = g3_ % 2
number_ = desk1 + desk1_ + desk2 + desk2_ + desk3 + desk3_
print(number_)



# input 
#20
#21
#22
# output 
#32
