Given the adjacency matrix of an undirected graph with `n` vertices, determine whether the graph is **complete**, i.e. there is an edge between every pair of distinct vertices. Print `DA` if the graph is complete, or `NU` otherwise. Input: The first line contains the natural number `n`. The following `n` lines each contain `n` binary values separated by spaces, representing the adjacency matrix. - `1 <= n <= 50` - a graph with a single vertex is considered complete (`K_1`) Output: The program prints to standard output the word `DA` or the word `NU`, followed by a newline character. Example: Input: 4 0 1 1 1 1 0 1 1 1 1 0 1 1 1 1 0 Output: DA