bounded-below.dfy(6,26): Error: decreases expression must be bounded below by 0 at end of loop iteration
 Asserted expression: 0 <= old@LoopEntry(i - start + 765) || i - start + 765 == old@LoopEntry(i - start + 765)
   with the label `LoopEntry` applied to the loop

Dafny program verifier finished with 0 verified, 1 error
