How can I define the variables express this in CVX.

\min\sum_{g=1}^G\sum_{i=1}^{N-1}\sum_{j=i+1}^{N}d_{ij}z_{ijg}

Here, d_{ij} are known and z_{ijg} are binary integer variables.

I define the variable as

```
variable Z(N,N,G) binary
```

But not able to express the objective function.