### Elements of a free group

My question is regarding the presentation of elements of the free group $F_2$.

```
G.<a,b,c> = FreeGroup()
G([1,1,2,-1,-3,2])
```

Then the result will be

```
a^2*b*a^-1*c^-1*b
```

Is there any ~~way ~~command to get the array? I mean we give $a^2*b*a^-1*c^-1*b$ then it returns [1,1,2,-1,-3,2].