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

public class Main {

    static int V, E;
    static double[][] dp;

    static boolean floydWarshall() {
        for (int k = 0; k < V; ++k) {
            for (int i = 0; i < V; ++i) {
                for (int j = 0; j < V; ++j) {
                    if (dp[i][k] + dp[k][j] < dp[i][j]) {
                        dp[i][j] = dp[i][k] + dp[k][j];
                    }
                }
            }
        }

        for (int k = 0; k < V; ++k) {
            for (int i = 0; i < V; ++i) {
                for (int j = 0; j < V; ++j) {
                    if (dp[i][k] + dp[k][j] < dp[i][j]) {
                        return false;
                    }
                }
            }
        }

        return true;
    }

    public static void main(String[] args) {
        FastScanner fs = new FastScanner();
        V = fs.nextInt();
        E = fs.nextInt();
        dp = new double[V][V];
        for (int i = 0; i < V; ++i) {
            Arrays.fill(dp[i], Double.POSITIVE_INFINITY);
            dp[i][i] = 0;
        }
        for (int i = 0; i < E; ++i) {
            int from = fs.nextInt();
            int to = fs.nextInt();
            int cost = fs.nextInt();
            dp[from][to] = cost;
        }

        if (floydWarshall()) {
            for (int i = 0; i < V; ++i) {
                for (int j = 0; j < V; ++j) {
                    if (dp[i][j] == Double.POSITIVE_INFINITY)
                        System.out.print("INF");
                    else
                        System.out.print((int)dp[i][j]);
                    if (j != V -1)
                        System.out.print(" ");
                }
                System.out.println();
            }
        } else {
            System.out.println("NEGATIVE CYCLE");
        }
    }
}

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 || nl > Integer.MAX_VALUE) throw new NumberFormatException();
        return (int) nl;
    }

    public double nextDouble() { return Double.parseDouble(next());}
}






























Measured memory_bytes: 32764