package contest171022;
import java.io.ByteArrayInputStream;
import java.io.IOException;
import java.io.InputStream;
import java.io.PrintWriter;
import java.util.Arrays;
import java.util.Comparator;
import java.util.InputMismatchException;

public class A {
	InputStream is;
	PrintWriter out;
	String INPUT = "";
	
	void solve()
	{
		int n = ni(), m = ni();
		int[][] rs = new int[m][];
		for(int i = 0;i < m;i++){
			rs[i] = new int[]{
					ni()*1440+ni()*60+ni(),
					ni()*1440+ni()*60+ni()+1
			};
		}
		Arrays.sort(rs, new Comparator<int[]>() {
			public int compare(int[] a, int[] b) {
				return a[0] - b[0];
			}
		});
		
		int ans = m;
		MinMaxHeap h = new MinMaxHeap(n+1);
		for(int[] r : rs){
			while(h.pos != 1 && h.min() <= r[0]){
				h.pollMin();
			}
			h.add(r[1]);
			if(h.pos > n+1){
				h.pollMax();
				ans--;
			}
		}
		out.println(ans);
	}
	
	public static class MinMaxHeap {
		public int[] a;
		public int n;
		public int pos;
		public static final int INF = Integer.MAX_VALUE;
		
		public MinMaxHeap(int n)
		{
			this.n = n;
			a = new int[n+1];
			this.pos = 1;
		}
		
		public void add(int x)
		{
			a[pos++] = x;
			int cur = pos-1;
			if(cur == 1)return;
			int par = cur>>>1;
			boolean ofmax = (31-Integer.numberOfLeadingZeros(cur)&1) == 1;
			if(a[cur] < a[par] ^ !ofmax){
				{int d = a[par]; a[par] = a[cur]; a[cur] = d;}
				cur = par;
				for(par = cur>>>2; par >= 1 && a[cur] < a[par] ^ !ofmax;cur>>>=2, par>>>=2){
					int d = a[par]; a[par] = a[cur]; a[cur] = d;
				}
			}else{
				// heapup in minlevel
				for(par = cur>>>2; par >= 1 && a[cur] < a[par] ^ ofmax;cur>>>=2, par>>>=2){
					int d = a[par]; a[par] = a[cur]; a[cur] = d;
				}
			}
		}
		
		public int pollMin()
		{
			int ret = min();
			if(pos >= 2){
				a[1] = a[--pos];
				down(1, false);
			}
			return ret;
		}
		
		private void down(int cur, boolean ofmax)
		{
			while(true){
				int minind = cur;
				if(2*cur < pos && a[2*cur] < a[minind] ^ ofmax)minind = 2*cur;
				if(2*cur+1 < pos && a[2*cur+1] < a[minind] ^ ofmax)minind = 2*cur+1;
				if(4*cur < pos && a[4*cur] < a[minind] ^ ofmax)minind = 4*cur;
				if(4*cur+1 < pos && a[4*cur+1] < a[minind] ^ ofmax)minind = 4*cur+1;
				if(4*cur+2 < pos && a[4*cur+2] < a[minind] ^ ofmax)minind = 4*cur+2;
				if(4*cur+3 < pos && a[4*cur+3] < a[minind] ^ ofmax)minind = 4*cur+3;
				if(minind == cur)break;
				
				{int d = a[cur]; a[cur] = a[minind]; a[minind] = d;}
				
				if(minind >= cur*4 && a[minind>>>1] < a[minind] ^ ofmax){
					int d = a[minind]; a[minind] = a[minind>>>1]; a[minind>>>1] = d;
				}
				cur = minind;
			}
		}
		
		public int min()
		{
			return pos < 2 ? INF : a[1];
		}
		
		public int max()
		{
			return pos < 2 ? INF : pos < 3 ? a[1] : pos < 4 ? a[2] : Math.max(a[2], a[3]);
		}
		
		public int pollMax()
		{
			if(pos < 2)return INF;
			if(pos < 3){
				pos--;
				return a[1];
			}
			if(pos < 4){
				pos--;
				return a[2];
			}
			int maxind = a[3] < a[2] ? 2 : 3;
			int ret = a[maxind];
			a[maxind] = a[--pos];
			down(maxind, true);
			return ret;
		}
	}
	
	void run() throws Exception
	{
		is = INPUT.isEmpty() ? System.in : new ByteArrayInputStream(INPUT.getBytes());
		out = new PrintWriter(System.out);
		
		long s = System.currentTimeMillis();
		solve();
		out.flush();
		if(!INPUT.isEmpty())tr(System.currentTimeMillis()-s+"ms");
//		Thread t = new Thread(null, null, "~", Runtime.getRuntime().maxMemory()){
//			@Override
//			public void run() {
//				long s = System.currentTimeMillis();
//				solve();
//				out.flush();
//				if(!INPUT.isEmpty())tr(System.currentTimeMillis()-s+"ms");
//			}
//		};
//		t.start();
//		t.join();
	}
	
	public static void main(String[] args) throws Exception { new A().run(); }
	
	private byte[] inbuf = new byte[1024];
	public int lenbuf = 0, ptrbuf = 0;
	
	private int readByte()
	{
		if(lenbuf == -1)throw new InputMismatchException();
		if(ptrbuf >= lenbuf){
			ptrbuf = 0;
			try { lenbuf = is.read(inbuf); } catch (IOException e) { throw new InputMismatchException(); }
			if(lenbuf <= 0)return -1;
		}
		return inbuf[ptrbuf++];
	}
	
	private boolean isSpaceChar(int c) { return !(c >= 33 && c <= 126); }
	private int skip() { int b; while((b = readByte()) != -1 && isSpaceChar(b)); return b; }
	
	private double nd() { return Double.parseDouble(ns()); }
	private char nc() { return (char)skip(); }
	
	private String ns()
	{
		int b = skip();
		StringBuilder sb = new StringBuilder();
		while(!(isSpaceChar(b))){ // when nextLine, (isSpaceChar(b) && b != ' ')
			sb.appendCodePoint(b);
			b = readByte();
		}
		return sb.toString();
	}
	
	private char[] ns(int n)
	{
		char[] buf = new char[n];
		int b = skip(), p = 0;
		while(p < n && !(isSpaceChar(b))){
			buf[p++] = (char)b;
			b = readByte();
		}
		return n == p ? buf : Arrays.copyOf(buf, p);
	}
	
	private int[] na(int n)
	{
		int[] a = new int[n];
		for(int i = 0;i < n;i++)a[i] = ni();
		return a;
	}
	
	private long[] nal(int n)
	{
		long[] a = new long[n];
		for(int i = 0;i < n;i++)a[i] = nl();
		return a;
	}
	
	private char[][] nm(int n, int m) {
		char[][] map = new char[n][];
		for(int i = 0;i < n;i++)map[i] = ns(m);
		return map;
	}
	
	private int[][] nmi(int n, int m) {
		int[][] map = new int[n][];
		for(int i = 0;i < n;i++)map[i] = na(m);
		return map;
	}
	
	private int ni() { return (int)nl(); }
	
	private long nl()
	{
		long num = 0;
		int b;
		boolean minus = false;
		while((b = readByte()) != -1 && !((b >= '0' && b <= '9') || b == '-'));
		if(b == '-'){
			minus = true;
			b = readByte();
		}
		
		while(true){
			if(b >= '0' && b <= '9'){
				num = num * 10 + (b - '0');
			}else{
				return minus ? -num : num;
			}
			b = readByte();
		}
	}
	
	private static void tr(Object... o) { System.out.println(Arrays.deepToString(o)); }
}