Count Letters recursive

def count_occurrences(t,l)
  if t == "" then
    return 0
  else
    if t[0,1] == l then
      return 1 + count_occurrences(t[1,t.length - 1], l)
    else
      return count_occurrences(t[1,t.length - 1], l)
    end
  end
end

#s = "hallo"
#puts(count_occurrences(s,'l'))

test = gets().chomp
letter = gets()[0,1]

puts(count_occurrences(test,letter))