proc sorted(s: string): string =
  if s.len <= 1: return s
  var lower:string = ""
  var upper:string = ""
  var pivot = s[0]
  for i in 1.. s.high:
    if s[i] < pivot: lower = lower & s[i]
    else: upper = upper & s[i]
  return sorted(lower) & pivot & sorted(upper)

var
  a = stdin.readLine
  b = stdin.readLine

echo if a.sorted == b.sorted: "YES" else: "NO"