# Variables r and R are gobbled

If implicit multiplication is not active, something like `4y^2`

should raise an error. This is what actually happens:

```
sage: var("y"); 4y^2
File "<ipython-input-22-25bcbc82148c>", line 1
var("y"); 4y**Integer(2)
^
SyntaxError: invalid syntax
```

If we replace `y`

by a different variable or consider a similar expression, we also get an error... except if the variable is `r`

or `R`

. For example,

```
sage: var("r, R"); 4r^2, 3R + 5r + 2R^3
(16, 16)
```

Surprisingly, there is no error. Variables `r`

and `R`

seem to be gobbled, so that SageMath parses `4r^2`

as `4**Integer(2)`

and `3R + 5r + 2R^3`

as `3 + 5 + 2**Integer(3)`

. Why? Is this a bug?