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