s = input()

a = s.count("0")
b = s.count("1")

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

a = s.count("0")
b = s.count("1")

print(min(a,b)*2)