A=int (input ())
B=[]
D=[]
C=0
La=True
For j in range (a) :
Da ppend (int (input ()))
B.a ppend ([])
For I in range (d) [j] :
B [j]. Append (list (map (int, input (). The split ())))
For j in range (a) :
T=1
For I in range (1, d [j]) :

For n in the range (0, t) :
If b [j] [I] [n].=0:
La=False
T=t + 1
If la:
Print (" YES ")
The else:
Print (" NO ")
I tested several groups of data, seems to be correct, is wrong?