from  collections import Counter

s = list(input())

c0 = s.count("0")
c1 = s.count("1")

print(min(c0, c1)*2) from  collections import Counter s = list(input()) s list(input()) list input() input c0 = s.count("0") c0 s.count("0") s.count s count "0" c1 = s.count("1") c1 s.count("1") s.count s count "1" print(min(c0, c1)*2) print min(c0, c1)*2 min(c0, c1) min c0 c1 2 s = list(input()) list(input()) s c1 = s.count("1") s.count("1") c1 c0 = s.count("0") s.count("0") c0
from  collections import Counter

s = list(input())

c0 = s.count("0")
c1 = s.count("1")

print(min(c0, c1)*2)