s = input()

zero = s.count('0')
one = s.count('1')

print(min(zero,one)*2) s = input() s input() input zero = s.count('0') zero s.count('0') s.count s count '0' one = s.count('1') one s.count('1') s.count s count '1' print(min(zero,one)*2) print min(zero,one)*2 min(zero,one) min zero one 2 one = s.count('1') s.count('1') one zero = s.count('0') s.count('0') zero s = input() input() s
s = input()

zero = s.count('0')
one = s.count('1')

print(min(zero,one)*2)