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Loops

Time limit 1 second
Memory limit 128 MiB

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 \le n \le 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