## Код:
```
i := 0; start := 0; end := ptroffset[ 0 ];
WHILE ( end # -1 ) & ( end - start < 4 ) DO 
  INC( i );
  start := end; 
  end := ptroffset[ i ];
END;
IF size - start < 4 THEN start := -1; END;
```
