S = input()

red = 0
blue = 0
for s in S:
    if s == '0':
        red += 1
    elif s == '1':
        blue += 1
print(min(red, blue)*2)
         S = input() S input() input red = 0 red 0 blue = 0 blue 0 for s in S:
    if s == '0':
        red += 1
    elif s == '1':
        blue += 1 s S if s == '0':
        red += 1
    elif s == '1':
        blue += 1 s == '0' s '0' red += 1 red 1 elif s == '1':
        blue += 1 s == '1' s '1' blue += 1 blue 1 print(min(red, blue)*2) print min(red, blue)*2 min(red, blue) min red blue 2 red += 1 1 red blue += 1 1 blue blue = 0 0 blue S = input() input() S red = 0 0 red
S = input()

red = 0
blue = 0
for s in S:
    if s == '0':
        red += 1
    elif s == '1':
        blue += 1
print(min(red, blue)*2)
        
