Clique#3418
Clique in an undirected graph is a subset of vertices such that every pair of vertices in the subset is connected by an edge. In other words, a clique is a complete subgraph of the original graph. The size of a clique is the number of vertices in it. Your task is to determine the size of the largest clique in the given graph.
The first line contains one integer — the number of test cases.
Each test case starts with a line containing two integers and (1 \leq N \leq 20,~ 0 \leq M \leq \frac{N(N-1)}{2}), where
— the number of vertices in the graph,
— the number of edges in the graph.
The next lines each contain two integers s_i and f_i (1 \leq s_i, f_i \leq N), indicating that there is an edge between vertex s_i and vertex f_i.
All pairs (s_i, f_i) are distinct. Each edge appears only once in the input. The graph has no multiple edges or loops (for each (s_i, f_i), s_i \neq f_i).
For each test case, output a single integer — the size of the largest clique in the corresponding graph.
Example 1