Grid

def main():
	ans = True
	n = int(input())
	rows = 0
	col = None
	for i in range(n):
		if not ans:
			input()
			continue
		l = list(map(int, list(input())))
		if sum(l) == n:
			rows += 1
		else:
			if col == None:
				col = l
			else:
				for j in range(len(l)):
					if l[j] != col[j]:
						print("-1")
						ans = False
	if not ans:
		return
	sr = rows
	sc = sum(col) if col is not None else 0
	if sr == n or sc == n:
		print(n)
	else:
		print(sr + sc)
		

main()

Test 1

Verdict: ACCEPTED

Test 2

Verdict: ACCEPTED

Test 3

Verdict: ACCEPTED

Test 4

Verdict: ACCEPTED

Test 5

Verdict: ACCEPTED

Test 6

Verdict: ACCEPTED

Test 7

Verdict: ACCEPTED

Test 8

Verdict: ACCEPTED

Test 9

Verdict: ACCEPTED

Test 10

Verdict: ACCEPTED

Test 11

Verdict: ACCEPTED

Test 12

Verdict: ACCEPTED

Test 13

Verdict: ACCEPTED

Test 14

Verdict: ACCEPTED

Test 15

Verdict: ACCEPTED

Test 16

Verdict: ACCEPTED

Test 17

Verdict: ACCEPTED

Test 18

Verdict: ACCEPTED

Test 19

Verdict: ACCEPTED

Test 20

Verdict: ACCEPTED

Test 21

Verdict: ACCEPTED

Test 22

Verdict: ACCEPTED