import java.io.IOException;
import java.io.InputStream;
import java.util.*;

public class Main {
	public static void main(String[] args) {
		FastScanner sc = new FastScanner();
		int v = sc.nextInt();
		int e = sc.nextInt();
		int[] s = new int[e];
		int[] t = new int[e];
		int[] d = new int[e];
		for (int i = 0; i < e; i++) {
			s[i] = sc.nextInt();
			t[i] = sc.nextInt();
			d[i] = sc.nextInt();
		}
		new WarshallFloyd(v, e, s, t, d).ans();
	}
}

class WarshallFloyd {
	static final int INF = Integer.MAX_VALUE;
	int v;
	int e;
	int[][] length;
	int[][] dp;
	public WarshallFloyd(int v, int e, int[] s, int[] t, int[] d) {
		this.v = v;
		this.e = e;
		length = new int[v][v];
		for (int i = 0; i < v; i++) {
			for (int j = 0; j < v; j++) {
				length[i][j] = INF;
			}
		}
		for (int i = 0; i < e; i++) {
			length[s[i]][t[i]] = d[i];
		}
	}
	void run() {
		dp = new int[v][v];
		for (int i = 0; i < v; i++) {
			for (int j = 0; j < v; j++) {
				if (i == j) {
					dp[i][j] = 0;
				} else {
					dp[i][j] = length[i][j];
				}
			}
		}
		for (int i = 0; i < v; i++) {
			for (int j = 0; j < v; j++) {
				for (int k = 0; k < v; k++) {
					if (dp[j][i] != INF && dp[i][k] != INF) {
						dp[j][k] = Math.min(dp[j][k], dp[j][i] + dp[i][k]);
					}
				}
			}
		}
	}
	boolean negative() {
		for (int i = 0; i < v; i++) {
			if (dp[i][i] < 0) {
				return true;
			}
		}
		return false;
	}
	public void ans() {
		run();
		if (negative()) {
			System.out.println("NEGATIVE CYCLE");
			return;
		}
		for (int i = 0; i < v; i++) {
			for (int j = 0; j < v; j++) {
				if (dp[i][j] == INF) {
					System.out.print("INF");
				} else {
					System.out.print(dp[i][j]);
				}
				if (j != v - 1) {
					System.out.print(" ");
				}
			}
			System.out.println();
		}
	}
}



class FastScanner {
	private final InputStream in = System.in;
	private final byte[] buffer = new byte[1024];
	private int ptr = 0;
	private int buflen = 0;
	private boolean hasNextByte() {
		if (ptr < buflen) {
			return true;
		} else {
			ptr = 0;
			try {
				buflen = in.read(buffer);
			} catch (IOException e) {
				e.printStackTrace();
			}
			if (buflen <= 0) {
				return false;
			}
		}
		return true;
	}
	private int readByte() {
		if (hasNextByte()) {
			return buffer[ptr++];
		} else {
			return -1;
		}
	}
	private static boolean isPrintableChar(int c) {
		return 33 <= c && c <= 126;
	}
	public boolean hasNext() {
		while (hasNextByte() && !isPrintableChar(buffer[ptr])) {
			ptr++;
		}
		return hasNextByte();
	}
	public String next() {
		if (!hasNext()) {
			throw new NoSuchElementException();
		}
		StringBuilder sb = new StringBuilder();
		int b = readByte();
		while (isPrintableChar(b)) {
			sb.appendCodePoint(b);
			b = readByte();
		}
		return sb.toString();
	}
	public long nextLong() {
		if (!hasNext()) {
			throw new NoSuchElementException();
		}
		long n = 0;
		boolean minus = false;
		int b = readByte();
		if (b == '-') {
			minus = true;
			b = readByte();
		}
		if (b < '0' || '9' < b) {
			throw new NumberFormatException();
		}
		while (true) {
			if ('0' <= b && b <= '9') {
				n *= 10;
				n += b - '0';
			} else if (b == -1 || !isPrintableChar(b)) {
				return minus ? -n : n;
			} else {
				throw new NumberFormatException();
			}
			b = readByte();
		}
	}
	public int nextInt() {
		long nl = nextLong();
		if (nl < Integer.MIN_VALUE || Integer.MAX_VALUE < nl) {
			throw new NumberFormatException();
		}
		return (int) nl;
	}
	public double nextDouble() {
		return Double.parseDouble(next());
	}
}


Measured memory_bytes: 33024