Problems
Loops
Loops
The adjacency matrix of an undirected graph is given. Determine whether it contains loops.
\InputFile
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.
\OutputFile
Print "\textbf{YES}" if graph contains loops and "\textbf{NO}" otherwise.
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