import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStreamReader;
import java.util.StringTokenizer;

public class Main {
	static int ans, N;
	static int[][] origin;

	public static void main(String[] args) throws NumberFormatException, IOException {
		BufferedReader br = new BufferedReader(new InputStreamReader(System.in));
		N = Integer.parseInt(br.readLine());
		origin = new int[N][N];

		ans = 0;
		for (int i = 0; i < N; i++) {
			StringTokenizer st = new StringTokenizer(br.readLine());
			for (int j = 0; j < N; j++) {
				origin[i][j] = Integer.parseInt(st.nextToken());
				ans = Math.max(origin[i][j], ans);
			}
		}

		direction(0, new int[5]);
		System.out.println(ans);
	}

	public static void direction(int cnt, int[] dir) {
		if (cnt >= 5) {
			int[][] copyMap = new int[N][N];
			for(int i=0; i<N; i++) {
				copyMap[i] = origin[i].clone();
			}
			findBigNum(dir, copyMap);
			return;
		}

		// 0:상, 1:하, 2:좌, 3:우
		for (int k = 0; k < 4; k++) {
			dir[cnt] = k;
			direction(cnt + 1, dir);
		}
	}

	public static void findBigNum(int[] dir, int[][] map) {
		for (int k = 0; k < 5; k++) {
			int[][] newMap = new int[N][N];
			// 상
			if (dir[k] == 0) {
				for (int i = 0; i < N; i++) {
					int idx = 0;
					for (int j = 0; j < N; j++) {
						if (map[j][i] != 0) {
							if (newMap[idx][i] == 0 || idx == j)
								newMap[idx][i] = map[j][i];
							else {
								int x = map[j][i] + newMap[idx][i];
								if ((x != 0) && ((x & (x - 1)) == 0)) { // 2의 제곱체크
									newMap[idx][i] = x;
									ans = Math.max(ans, x);
									idx++;
								} else {
									idx++;
									newMap[idx][i] = map[j][i];
								}
							}
						}
					}
				}
			}
			// 하
			if (dir[k] == 1) {
				for (int i = 0; i < N; i++) {
					int idx = N - 1;
					for (int j = N - 1; j >= 0; j--) {
						if (map[j][i] != 0) {
							if (newMap[idx][i] == 0 || idx == j)
								newMap[idx][i] = map[j][i];
							else {
								int x = map[j][i] + newMap[idx][i];
								if ((x != 0) && ((x & (x - 1)) == 0)) { // 2의 제곱체크
									newMap[idx][i] = x;
									ans = Math.max(ans, x);
									idx--;
								} else {
									idx--;
									newMap[idx][i] = map[j][i];
								}
							}
						}
					}
				}
			}
			// 좌
			if (dir[k] == 2) {
				for (int i = 0; i < N; i++) {
					int idx = 0;
					for (int j = 0; j < N; j++) {
						if (map[i][j] != 0) {
							if (newMap[i][idx] == 0 || idx == j)
								newMap[i][idx] = map[i][j];
							else {
								int x = map[i][j] + newMap[i][idx];
								if ((x != 0) && ((x & (x - 1)) == 0)) { // 2의 제곱체크
									newMap[i][idx] = x;
									ans = Math.max(ans, x);
									idx++;
								} else {
									idx++;
									newMap[i][idx] = map[i][j];
								}
							}
						}
					}
				}
			}
			// 우
			if (dir[k] == 3) {
				for (int i = 0; i < N; i++) {
					int idx = N - 1;
					for (int j = N - 1; j >= 0; j--) {
						if (map[i][j] != 0) {
							if (newMap[i][idx] == 0 || idx == j)
								newMap[i][idx] = map[i][j];
							else {
								int x = map[i][j] + newMap[i][idx];
								if ((x != 0) && ((x & (x - 1)) == 0)) { // 2의 제곱체크
									newMap[i][idx] = x;
									ans = Math.max(ans, x);
									idx--;
								} else {
									idx--;
									newMap[i][idx] = map[i][j];
								}
							}
						}
					}
				}
			}
			map = newMap;
		}
	}
}