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