# Labeling vertices of a graph effectively

Suppose I have $k$ copies of the $5$- cliques formed by using the following code:

```
def Sier(n,k):
l=list(range(1,k))
g=graphs.CompleteGraph(n)
for i in l:
g=g.disjoint_union(graphs.CompleteGraph(n))
return g
k=Sier(5,5)
```

How do I label the vertices in the manner $ij$ where $i$ stands for the $i$-th copy and $j$ for the $j$-th vertex in the $i$-th copy of the clique?