The graphs of the straight lines with equations `5y + 4x = 40` and `y = x + 1` have been drawn on the grid.

`5y + 4x > 40`

`y < x + 1`

`x < a`

`x` and `y` are integers.

`a` is an integer constant.

There are `4` integer points on the grid that satisfy all three inequalities.

Find the value of `a`.