using System;
using System.Collections.Generic;
using System.IO;
using System.Linq;
using System.Numerics;
using static System.Math;

namespace CSharpSpiral {
	class Program {
		public static void Main(string[] args) {
			var sw = new StreamWriter(Console.OpenStandardOutput()) {
				AutoFlush =
#if DEBUG
			true
#else
			false
#endif
			};
			Console.SetOut(sw);
			new Program().Solve(new ConsoleInput(
#if DEBUG
			new StreamReader("../../../inputData.txt")
#else
			Console.In
#endif
			, ' '));
			Console.Out.Flush();
		}

		public void Solve(ConsoleInput cin) {
			int N = cin.ReadInt, M = cin.ReadInt;
			var U = new UnionFindForest(N);
			for(int m = 0; m < M; m++) {
				var datum = cin.ReadIntArray(2);
				U.Union(datum[0]-1, datum[1]-1);
			}
			Console.WriteLine(U.Degrees().Max());
		}

	}

	class UnionFindForest {
		public class Node {
			public int value { get; set; }
			public virtual Node parent { get; set; }
			public virtual Node root {
				get {
					var path = new Queue<Node>();
					var res = this;
					while(res.parent != res) {
						path.Enqueue(res);
						res = res.parent;
					}
					while(path.Any())
						path.Dequeue().parent = res;
					return res;
				}
			}
			public int rank { get; private set; }    //meanful iff root
			public void rankIncrement() => rank++;
			public Node(int _value) {
				value = _value;
				parent = this;
				rank = 1;
			}
		}

		private readonly Dictionary<int, Node> Registry = new Dictionary<int, Node>();
		public UnionFindForest(int N) {
			for(int i = 0; i < N; i++) Add(i);
		}
		public void Union(int x, int y) => Union(Registry[x], Registry[y]);
		public void Union(Node X, Node Y) {
			var RX = X.root;
			var RY = Y.root;
			switch(RX.rank.CompareTo(RY.rank)) {
				case 1:
					RY.parent = RX;
					break;
				case -1:
					RX.parent = RY;
					break;
				default:
					RX.parent = RY;
					RY.rankIncrement();
					break;
			}
		}
		public bool Find(int x, int y) => Find(Registry[x], Registry[y]);
		public bool Find(Node X, Node Y) => X.root == Y.root;
		public virtual void Add(int id) {
			var n = new Node(id);
			Registry.Add(id, n);
		}
		public Dictionary<Node, int> TallyDegrees() {
			var Roots = new Dictionary<Node, int>();
			foreach(var node in Registry.Values) {
				if(Roots.Keys.Contains(node.root))
					Roots[node.root]++;
				else
					Roots.Add(node.root, 1);
			}
			return Roots;
		}
		public int[] Degrees() {
			var D = TallyDegrees();
			var res = new int[Registry.Count];
			for(int i = 0; i < Registry.Count; i++)
				res[i] = D[Registry[i].root];
			return res;
		}
		public int TreeCount() {
			var D = TallyDegrees();
			return D.Count;
		}
	}
	static class ExtendClass {
		public static string Join<T>(this IEnumerable<T> X, string separator = " ")
			=> string.Join(separator, X);
	}
	class ConsoleInput {
		private readonly TextReader _stream;
		private readonly char _separator = ' ';
		private readonly Queue<string> inputStream;
		public ConsoleInput(TextReader stream, char separator = ' ') {
			this._separator = separator;
			this._stream = stream;
			inputStream = new Queue<string>();
		}
		public string Read {
			get {
				if(inputStream.Count != 0) return inputStream.Dequeue();
				string[] tmp = _stream.ReadLine().Split(_separator);
				for(int i = 0; i < tmp.Length; ++i)
					inputStream.Enqueue(tmp[i]);
				return inputStream.Dequeue();
			}
		}
		public string ReadLine { get { return _stream.ReadLine(); } }
		public int ReadInt { get { return int.Parse(Read); } }
		public long ReadLong { get { return long.Parse(Read); } }
		public double ReadDouble { get { return double.Parse(Read); } }
		public string[] ReadStrArray(long N) {
			var ret = new string[N];
			for(long i = 0; i < N; ++i)
				ret[i] = Read;
			return ret;
		}
		public int[] ReadIntArray(long N) { var ret = new int[N]; for(long i = 0; i < N; ++i) ret[i] = ReadInt; return ret; }
		public long[] ReadLongArray(long N) { var ret = new long[N]; for(long i = 0; i < N; ++i) ret[i] = ReadLong; return ret; }
		public double[] ReadDoubleArray(long N) { var ret = new double[N]; for(long i = 0; i < N; ++i) ret[i] = ReadDouble; return ret; }
		public bool isEOF {
			get { return _stream.Peek() == -1; }
		}
	}

}


Measured memory_bytes: 74892