Symmetric Matrix
Given a square matrix. Check if it is symmetrical with respect to
main diagonal.
Input data. The INPUT.TXT file contains the number n (0<n<=100).
The next n lines contain n integers each from -32768 to 32767.
Output. Output YES,
to the OUTPUT.TXT file
if the matrix is symmetric with respect to the main diagonal, otherwise output NO.
Example INPUT.TXT
file
3
1 2 3
2 4 5
3 5 6
Example OUTPUT.TXT
YES