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import java.util.HashSet;
import java.util.ArrayList;
import java.util.Arrays;

class Solution {
    public int solution(int n, int[][] edge) {
        int answer = 0;
        int length = edge.length;
        int[][] line = new int[n][n];
        HashSet<Integer> hs = new HashSet<Integer>();
        ArrayList<Integer> al = new ArrayList<Integer>();
        int[] arr = new int[n];

        for(int i=0; i<length; i++){
            int a = edge[i][0] -1;
            int b = edge[i][1] -1;
            line[a][b] =1;
            line[b][a] =1;
        }

        hs.add(0);
        al.add(0);
        while(hs.size()<n){
            int v = al.remove(0);
            for(int i=0; i<n; i++){
                if(line[v][i] == 1 && !hs.contains(i)){
                    hs.add(i);
                    al.add(i);
                    arr[i] = arr[v]+1;
                }
            }
        }

        int max =0;
        int count = 0;
        for(int i=0; i<n; i++){
            if(max < arr[i]){
                max = arr[i];
                count = 1;
            }else if(max == arr[i]){
                count++;
            }
        }
        answer = count;

        return answer;
    }
}