How to find how many values are divisible in to certain value in 2d array in python

The following code generate random number of 2d arrays and I want to print how many values in each pair are divisible to 3. For example assume we have an array [[2, 10], [1, 6], [4, 8]]. So the first pair which is [2,10] has 3 ,6 and 9 which are totally 3 and second pair has 3 and 6 which are totally two and last pair[4,8] has just 1 divisible to 3 which is 6. Therefore, The final out put should print sum of total number of divisible values which is 3+2+1=6

a=random.randint(1, 10)

b = np.random.randint(1,10,(a,2))
b = [sorted(i) for i in b]   
c = np.array(b)            
   
counter = 0;   
  
for i in range(len(c)): 
    d=(c[i,0],c[i,1])
    if (i % 3 == 0):  
        counter = counter + 1
print(counter)