from collections import Counter

S = list(input())

count = Counter(S)
n = min(count['0'], count['1'])
print(n * 2)
 from collections import Counter S = list(input()) S list(input()) list input() input count = Counter(S) count Counter(S) Counter S n = min(count['0'], count['1']) n min(count['0'], count['1']) min count['0'] count '0' count['1'] count '1' print(n * 2) print n * 2 n 2 count = Counter(S) Counter(S) count S = list(input()) list(input()) S n = min(count['0'], count['1']) min(count['0'], count['1']) n
from collections import Counter

S = list(input())

count = Counter(S)
n = min(count['0'], count['1'])
print(n * 2)

