import collections
s = list(input())
c = collections.Counter(s)
print(min(c["0"], c["1"])*2) import collections collections s = list(input()) s list(input()) list input() input c = collections.Counter(s) c collections.Counter(s) collections.Counter collections Counter s print(min(c["0"], c["1"])*2) print min(c["0"], c["1"])*2 min(c["0"], c["1"]) min c["0"] c "0" c["1"] c "1" 2 c = collections.Counter(s) collections.Counter(s) c s = list(input()) list(input()) s
import collections
s = list(input())
c = collections.Counter(s)
print(min(c["0"], c["1"])*2)