(define (System.out.println x)
  (begin
    (display x)
    (newline)
  )
)

(let (
      (SA (symbol->string (read)))
      (PA (read))
      (XA (symbol->string (read)))
     )
  (let (
        (SB (symbol->string (read)))
        (PB (read))
        (XB (symbol->string (read)))
       )
    (if (= PA PB)
        (System.out.println "-1")
        (if (> PA PB)
            (System.out.println SA)
            (System.out.println SB)
        )
    )
  )
)