s=input()
a=s.count('0')
b=s.count('1')
c=min(a,b)
print(2*c) s=input() s input() input a=s.count('0') a s.count('0') s.count s count '0' b=s.count('1') b s.count('1') s.count s count '1' c=min(a,b) c min(a,b) min a b print(2*c) print 2*c 2 c a=s.count('0') s.count('0') a b=s.count('1') s.count('1') b s=input() input() s c=min(a,b) min(a,b) c
s=input()
a=s.count('0')
b=s.count('1')
c=min(a,b)
print(2*c)