3gp

1
3gp           
3
19
1
{a, b, c, d}          #generators 
{(b * c^-1 * d)^-3, (c * d^-1)^3, [b, a] = c^-1, [c, a], [c, b] = d^-1 }
0          #exponent  

2
3GP

0