n, m = gets.chomp.split.map(&:to_i)
s = gets.chomp

ac = 0
while s.scan("AC").length != 0
  ac += 1
  s.sub!("AC", "")
end
wa = 0
while s.scan("WA").length != 0
  wa += 1
  s.sub!("WA", "")
end

if n == wa && m == ac
  puts "Yes"
else
  puts "No"
end