S = input()
zero = S.count("0")
one = len(S) - zero

print(min(zero, one)*2) S = input() S input() input zero = S.count("0") zero S.count("0") S.count S count "0" one = len(S) - zero one len(S) - zero len(S) len S zero print(min(zero, one)*2) print min(zero, one)*2 min(zero, one) min zero one 2 zero = S.count("0") S.count("0") zero one = len(S) - zero len(S) - zero one S = input() input() S
S = input()
zero = S.count("0")
one = len(S) - zero

print(min(zero, one)*2)