abc = gets.chomp.to_i
abc1 = gets.chomp.to_i
abc2 = gets.chomp.to_i
akun = abc
bkun = abc1
ckun = abc2

d = [akun,bkun,ckun]
e = d.sort.reverse

if d.index(e[0]) == 0 then
  puts "A"
end
if d.index(e[0]) == 1 then
  puts "B"
end
if d.index(e[0]) == 2 then
  puts "C" 
end
if d.index(e[1]) == 0 then
  puts "A"
end
if d.index(e[1]) == 1 then
  puts "B"
end
if d.index(e[1]) == 2 then
  puts "C"
end
if d.index(e[2]) == 0 then
  puts "A"
end
if d.index(e[2]) == 1 then
  puts "B"
end
if d.index(e[2]) == 2 then
  puts "C"
end