n,m,k=map(int, input().split())
data=list(map(int, input().split()))for i in data:print(i)
#consequence=2 3 4 5 6 
for i in data:print(max(i))

#consequence= TypeError: 'int' object is not iterable

If int is iterable, then why I can use int in for loop? Why I cannot use max() function in this case?

You can use max(x) like this:

data = [1,2,3,4,5]
max(m) # result 5

Int is not iterable but list is iterable. If you iterate you iterate trought list in for loop. How you use a for loop to find maximum doesnt make sense. Beacuse for every particular intiger you try to find a maximum. You can use this method as input of list.