import java.io.IOException;
import java.io.InputStream;
import java.io.PrintWriter;
//import java.util.LinkedList;
//import java.util.Arrays;
import java.util.NoSuchElementException;
//import java.util.PriorityQueue;


public class Main{
	static FastScanner sc = new FastScanner();
	static PrintWriter out = new PrintWriter(System.out);
	//static String S;
	static int n;
	static int m;
	//static LinkedList <Integer> adj[]; 
	//static PriorityQueue <Integer> q;
	static boolean g [][];
	static boolean visited [];
	
	public static void main(String[] args) {
		n = sc.nextInt();
		m = sc.nextInt();
		
		int a [] = new int [50];
		int b [] = new int [50];
		g = new boolean [50][50];
		
		for (int i=0; i<m; i++) {
			a[i] = sc.nextInt()-1;
			b[i] = sc.nextInt()-1;
			g[a[i]][b[i]] = g[b[i]][a[i]] = true;
		}
		
		int ans = 0;
		for (int i=0; i<m; i++) {
			g[a[i]][b[i]] = g[b[i]][a[i]] = false;
			
			visited = new boolean [50];
			
			DFS(0);
			boolean flag = false;
			for (int j=0; j<n; j++) {
				if (!visited[j]) {
					flag = true;
					break;
				}
			}
			if (flag)
				ans++;
			
			g[a[i]][b[i]] = g[b[i]][a[i]] = true;
		}
		out.println(ans);
		out.flush();
	}
	
	static void DFS (int v) { 
    	visited[v] = true;
    	
    	for (int v2=0; v2<n; v2++) {
    		if (!g[v][v2])
    			continue;
    		if (visited[v2])
    			continue;
    		DFS(v2);
    	}
    } 
	
		static class FastScanner {
		    private final InputStream in = System.in;
		    private final byte[] buffer = new byte[1024];
		    private int ptr = 0;
		    private int buflen = 0;

		    private boolean hasNextByte() {
		      if (ptr < buflen) {
		        return true;
		      } else {
		        ptr = 0;
		        try {
		          buflen = in.read(buffer);
		        } catch (IOException e) {
		          e.printStackTrace();
		        }
		        if (buflen <= 0) {
		          return false;
		        }
		      }
		      return true;
		    }

		    private int readByte() {
		      if (hasNextByte()) return buffer[ptr++];
		      else return -1;
		    }

		    private static boolean isPrintableChar(int c) {
		      return 33 <= c && c <= 126;
		    }

		    private void skipUnprintable() {
		      while (hasNextByte() && !isPrintableChar(buffer[ptr])) ptr++;
		    }

		    public boolean hasNext() {
		      skipUnprintable();
		      return hasNextByte();
		    }

		    public String next() {
		      if (!hasNext()) throw new NoSuchElementException();
		      StringBuilder sb = new StringBuilder();
		      int b = readByte();
		      while (isPrintableChar(b)) {
		        sb.appendCodePoint(b);
		        b = readByte();
		      }
		      return sb.toString();
		    }

		    public long nextLong() {
		      if (!hasNext()) throw new NoSuchElementException();
		      long n = 0;
		      boolean minus = false;
		      int b = readByte();
		      if (b == '-') {
		        minus = true;
		        b = readByte();
		      }
		      if (b < '0' || '9' < b) {
		        throw new NumberFormatException();
		      }
		      while (true) {
		        if ('0' <= b && b <= '9') {
		          n *= 10;
		          n += b - '0';
		        } else if (b == -1 || !isPrintableChar(b)) {
		          return minus ? -n : n;
		        } else {
		          throw new NumberFormatException();
		        }
		        b = readByte();
		      }
		    }

		    public int nextInt() {
		      return (int) nextLong();
		    }

		    public int[] nextIntArray(int N, boolean oneBased) {
		      if (oneBased) {
		        int[] array = new int[N + 1];
		        for (int i = 1; i <= N; i++) {
		          array[i] = sc.nextInt();
		        }
		        return array;
		      } else {
		        int[] array = new int[N];
		        for (int i = 0; i < N; i++) {
		          array[i] = sc.nextInt();
		        }
		        return array;
		      }
		    }

		    public long[] nextLongArray(int N, boolean oneBased) {
		      if (oneBased) {
		        long[] array = new long[N + 1];
		        for (int i = 1; i <= N; i++) {
		          array[i] = sc.nextLong();
		        }
		        return array;
		      } else {
		        long[] array = new long[N];
		        for (int i = 0; i < N; i++) {
		          array[i] = sc.nextLong();
		        }
		        return array;
		      }
		    }
		  }

		}	 





Measured memory_bytes: 21460