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