Problems
Loops
Loops
The adjacency matrix of an undirected graph is given. Determine whether it contains loops.
Input data
The first line contains the number of vertices n (1 ≤ n ≤ 100). Then given n lines with n elements in each - the description of adjacency matrix.
Output data
Print "YES" if graph contains loops and "NO" otherwise.
Examples
Input example #1
3 0 1 1 1 0 1 1 1 0
Output example #1
NO
Input example #2
3 0 1 0 1 1 1 0 1 0
Output example #2
YES