S = input()
c0 = 0
c1 = 0
for s in S:
    if s == "0":
        c0 += 1
    else:
        c1 += 1

print(2*min(c0, c1)) S = input() S input() input c0 = 0 c0 0 c1 = 0 c1 0 for s in S:
    if s == "0":
        c0 += 1
    else:
        c1 += 1 s S if s == "0":
        c0 += 1
    else:
        c1 += 1 s == "0" s "0" c0 += 1 c0 1 c1 += 1 c1 1 print(2*min(c0, c1)) print 2*min(c0, c1) 2 min(c0, c1) min c0 c1 S = input() input() S c1 = 0 0 c1 c1 += 1 1 c1 c0 = 0 0 c0 c0 += 1 1 c0
S = input()
c0 = 0
c1 = 0
for s in S:
    if s == "0":
        c0 += 1
    else:
        c1 += 1

print(2*min(c0, c1))