s = input()
s0 = s.count('0')
s1= s.count('1')
print(2*min(s0,s1)) s = input() s input() input s0 = s.count('0') s0 s.count('0') s.count s count '0' s1= s.count('1') s1 s.count('1') s.count s count '1' print(2*min(s0,s1)) print 2*min(s0,s1) 2 min(s0,s1) min s0 s1 s = input() input() s s0 = s.count('0') s.count('0') s0 s1= s.count('1') s.count('1') s1
s = input()
s0 = s.count('0')
s1= s.count('1')
print(2*min(s0,s1))