import java.util.*;

public class _1389 {
    public static void main(String[] args) {
        Scanner sc = new Scanner(System.in);
        String[] input = sc.nextLine().split(" ");
        int N = Integer.parseInt(input[0]);
        int M = Integer.parseInt(input[1]);

        int[][] distance = new int[N+1][N+1];
        for(int i=0; i<M; i++){
            String[] linked_input = sc.nextLine().split(" ");
            int a = Integer.parseInt(linked_input[0]);
            int b = Integer.parseInt(linked_input[1]);
            distance[a][b] = 1;
            distance[b][a] = 1;
        }
        sc.close();

        int maxValue = 1000000;
        for(int i=1; i<=N; i++){
            for(int j=1; j<=N; j++){
                if(i==j) distance[i][j] = 0;
                else if(distance[i][j] == 0) distance[i][j] = maxValue;
            }
        }

        for(int k=1; k<=N; k++){
            for(int i=1; i<=N; i++){
                for(int j=1; j<=N; j++){
                    distance[i][j] = Math.min(distance[i][j], distance[i][k] + distance[k][j]);
                }
            }
        }

        int[] result = new int[N+1];
        int minDistance = maxValue;
        int result_person = 0;
        for(int i=1; i<=N; i++){
            for (int j = 1; j <= N; j++) {
                result[i] += distance[i][j];
            }
            if(minDistance>result[i]){
                result_person = i;
                minDistance = result[i];
            }
        }
        System.out.println(result_person);
    }
}