L=sorted(map(int,input().split()))
#print(L)
c=L[0]
L=[i-c for i in L]
#print(L,c)
m=(L[2]-L[1])//2
L=[m,L[1],L[2]-m*2]
#print(L,c)
c+=L[0]
L=[i-m for i in L]
#print(L,c)
m=L[1]//2
m-=m%2
L=[m,L[1]-m,L[2]-m]
#print(L,c)
c+=L[0]
L=[i-m for i in L]
print(c)