S = input()

zero_count=S.count("0")
one_count=S.count("1")

ans=2*min(int(zero_count),int(one_count))
print(ans) S = input() S input() input zero_count=S.count("0") zero_count S.count("0") S.count S count "0" one_count=S.count("1") one_count S.count("1") S.count S count "1" ans=2*min(int(zero_count),int(one_count)) ans 2*min(int(zero_count),int(one_count)) 2 min(int(zero_count),int(one_count)) min int(zero_count) int zero_count int(one_count) int one_count print(ans) print ans one_count=S.count("1") S.count("1") one_count S = input() input() S ans=2*min(int(zero_count),int(one_count)) 2*min(int(zero_count),int(one_count)) ans zero_count=S.count("0") S.count("0") zero_count
S = input()

zero_count=S.count("0")
one_count=S.count("1")

ans=2*min(int(zero_count),int(one_count))
print(ans)