Description cherish spring jia, one of the 12 women of jinling, she is the youngest of four sisters jia family, ningguo mansion Gu Jing daught, Gu Zhen younger sister, because father Gu Jing blindly good way an alchemist, something else has none, and the mother also died young, she's been rong-guo mansion jia life growing up, because no parents love, developed the character of lonely cold, heart cold mouth cold, indifferent to the tears of sadness of others, because cherish spring little sister is too cold, so her side of things would be hurt by her cold, even so, the zealous you still want to cherish the spring to humanize, cherish spring is now standing at a n * n (n is an odd number of) subject in the middle of the matrix, the matrix of every point has certain cold value aij, cold value matrix from the center to spread out and chill diminishing value and the difference is 1, the farther away from the center point of the cold point will gradually reduce, cherish spring want to test your eyesight now, if you can recognise a current matrix is in line with this requirement (see sample) and precious little spring will say "ok, you are a cool guy.", or cherish spring will be disappointed and you will be Shouting "It 's too cold."
Input the first line is a positive integer n, on behalf of the matrix (1 n 999) or less or less length, followed by a matrix of n * n, (? 1000 aij acuities were 1000 or less),
Meet the requirements for the subject, and the Output if the current matrix, please Output "ok, you are a cool guy.", otherwise, please Output "It 's too cold."
Samples
Input
3
1 1 1
1 2 1
1 1 1
The output
Ok, you are a cool guy.
Input
5
1 1 1 1 1
1 2 2 2 1
1 2 3 2 1
1 2 2 2 1
1 1 1 1 1
The output
Ok, you are a cool guy.
Input
7
1 1 1 1 1 1 1
1 2 2 2 2 2 1
1 2 3 3 3 2 1
1 2 3 3 3 2 1
1 2 3 3 3 2 1
1 2 2 2 2 2 1
1 1 1 1 1 1 1
The output
It 's too cold.
Input
7
- 1-1-1-1-1-1-1
1 0 0 0 0 0-1
1 1 1 0 0-1
1 0 1 2 1 0-1
1 1 1 0 0-1
1 0 0 0 0 0-1
- 1-1-1-1-1-1-1
The output
Ok, you are a cool guy.
Hint the third sample points do not conform to the conditions, because there is no present decreasing outward from a center, in the form of