Grid

#include <bits/stdc++.h>

using namespace std;

int n, rdk[1010][1010], vaaka[1010], pysty[1010], ans, lsk;
char cha;

int main() {
	cin >> n;
	bool kaikki = false;
	for(int i=0; i<n; i++) {
	int cnt = 0;
		for(int j=0; j<n; j++) {
			cin >> cha;
			rdk[j][i] = cha-'0';
			if(rdk[j][i]) {
			 cnt++;
			 lsk++;
			 }
		}
		if(cnt==n)
		ans++;
		else if(cnt) {
			kaikki = true;
			ans = 0;
		}

	}
	if(kaikki) {
		if(lsk==n*n) {
		cout << n;
		} else
		cout << -1;
		
		exit(0);
	}
	if(ans<n) {
	for(int i=0; i<n; i++) {
		int cnt = 0;
		for(int j=0; j<n; j++) {
			if(rdk[i][j])
				cnt++;
		}
		if(cnt==n)
		ans++;
		else if(cnt) {
		cout << -1;
			exit(0);
		}
	}
	}
	cout << ans;
}

Test 1

Verdict: ACCEPTED

Test 2

Verdict: ACCEPTED

Test 3

Verdict: ACCEPTED

Test 4

Verdict: ACCEPTED

Test 5

Verdict: WRONG ANSWER

Test 6

Verdict: WRONG ANSWER

Test 7

Verdict: ACCEPTED

Test 8

Verdict: ACCEPTED

Test 9

Verdict: WRONG ANSWER

Test 10

Verdict: WRONG ANSWER

Test 11

Verdict: WRONG ANSWER

Test 12

Verdict: WRONG ANSWER

Test 13

Verdict: WRONG ANSWER

Test 14

Verdict: WRONG ANSWER

Test 15

Verdict: WRONG ANSWER

Test 16

Verdict: ACCEPTED

Test 17

Verdict: ACCEPTED

Test 18

Verdict: WRONG ANSWER

Test 19

Verdict: WRONG ANSWER

Test 20

Verdict: WRONG ANSWER

Test 21

Verdict: WRONG ANSWER

Test 22

Verdict: ACCEPTED