S = input()
total = 0
count_0 = S.count("0")
count_1 = S.count("1")
ans = min(count_0, count_1) * 2
print(ans) S = input() S input() input total = 0 total 0 count_0 = S.count("0") count_0 S.count("0") S.count S count "0" count_1 = S.count("1") count_1 S.count("1") S.count S count "1" ans = min(count_0, count_1) * 2 ans min(count_0, count_1) * 2 min(count_0, count_1) min count_0 count_1 2 print(ans) print ans S = input() input() S count_1 = S.count("1") S.count("1") count_1 total = 0 0 total count_0 = S.count("0") S.count("0") count_0 ans = min(count_0, count_1) * 2 min(count_0, count_1) * 2 ans
S = input()
total = 0
count_0 = S.count("0")
count_1 = S.count("1")
ans = min(count_0, count_1) * 2
print(ans)