Roni writes a check for $700 to Sela. Sela indorses the check in blank and transfers it

Question:

Roni writes a check for $700 to Sela. Sela indorses the check in blank and transfers it to Titus, who alters the check to read $7,000 and presents it to Union Bank, the drawee, for payment. The bank cashes it. Roni discovers the alteration and sues the bank. How much, if anything, can Roni recover? From whom can the bank recover this amount?