import java.util.*;
public class floydWarshall{
    static void print(int u, int v, int[][]next){
        if(next[u][v]==-1){
            System.out.println("no path exists");
            return;
        }
        System.out.print(u);
        while(u!=v){
            u = next[u][v];
            System.out.print("->"+u);

        } 
        System.out.println();

    }

    public static void main(String[] args){
        Scanner sc = new Scanner(System.in);
        System.out.print("\nEnter number of vertices: ");
        int n = sc.nextInt();
        int[][] graph = new int[n][n];

        System.out.println("Enter distance matrix: ");
        for(int i =0;i<n;i++){
            for(int j =0;j<n;j++){
                graph[i][j] = sc.nextInt();
            }
        }
        int[][] next = new int[n][n];
        int[][] dist = new int[n][n];
        for(int i = 0;i<n;i++){
            for(int j =0;j<n;j++){
                dist[i][j] = graph[i][j];
                if(graph[i][j]!=999 && i!=j)
                    next[i][j] = j;
                else
                    next[i][j] = -1;
            }
        }
        for(int k =0;k<n;k++){
            for(int i=0;i<n;i++){
                for(int j=0;j<n;j++){
                    if(dist[i][k]!=999 && dist[k][j]!= 999 && dist[i][k]+dist[k][j]< dist[i][j]){
                        dist[i][j] = dist[i][k] + dist[k][j];
                        next[i][j] = next[i][k];
                    }
                }
            }
        }
        boolean negativeCycle = false;
        for(int i=0;i<n;i++){
            if(dist[i][i]<0){
                negativeCycle = true;
                break;
            }
        }
        if(negativeCycle){
            System.out.println("Negative cycle exists");

        }else{
            System.out.println("No negative cycle");
        }
        System.out.println("Shortest path matrix");
        for(int i=0;i<n;i++){
            for(int j=0;j<n;j++){
                System.out.print(dist[i][j]+ " ");
            }
            System.out.println();
        }
        System.out.print("\nEnter source vertex: ");
        int u = sc.nextInt();
        System.out.print("\nENter dest vertex: ");
        int v = sc.nextInt();
        System.out.print("\nShortes path: ");
        print(u,v,next);

        System.out.println("Cost: "+ dist[u][v]);
        sc.close();

    }
}