S = input()
c = S.count("0")
l = len(S)
print(l-abs(c-(l-c))) S = input() S input() input c = S.count("0") c S.count("0") S.count S count "0" l = len(S) l len(S) len S print(l-abs(c-(l-c))) print l-abs(c-(l-c)) l abs(c-(l-c)) abs c-(l-c) c l-c l c l = len(S) len(S) l S = input() input() S c = S.count("0") S.count("0") c
S = input()
c = S.count("0")
l = len(S)
print(l-abs(c-(l-c)))