import java.io.IOException;
import java.io.InputStream;
import java.io.PrintWriter;
import java.util.ArrayDeque;
import java.util.ArrayList;
import java.util.NoSuchElementException;

public class Main {

	void solve() {
		n = in.nextInt();
		m = in.nextInt();
		int[] a = new int[m];
		int[] b = new int[m];
		for (int i = 0; i < m; i++) {
			a[i] = in.nextInt() - 1;
			b[i] = in.nextInt() - 1;
		}
		int ret = m;
		for (int i = 0; i < m; i++) {
			boolean[][] table = new boolean[n][n];
			for (int j = 0; j < m; j++) {
				table[a[j]][b[j]] = true;
				table[b[j]][a[j]] = true;
			}
			for (int j = 0; j < n; j++) {
				table[j][j] = true;
			}
			// delete i
			table[a[i]][b[i]] = false;
			table[b[i]][a[i]] = false;

			for (int post = 0; post < n; post++) {
				for (int from = 0; from < n; from++) {
					for (int to = 0; to < n; to++) {
						table[from][to] = table[from][to] || (table[from][post] && table[post][to]);
					}
				}
			}
			if (table[a[i]][b[i]]) {
				ret--;
			}
		}
		out.println(ret);
	}

	// only call
	public static void main(String[] args) {
		new Main().solve();
		out.flush();
	}

	// predefined
	FastScanner in = new FastScanner(System.in);
	static PrintWriter out = new PrintWriter(System.out);

	int n, m, a, b, c, d, e, f;
	ArrayList<Integer> list = new ArrayList<>();
	ArrayDeque<Integer> q = new ArrayDeque<>();

	// 2D-map
	int H, W;
	final int[] dw = new int[] { 0, 1, 0, -1, 1, 1, -1, -1 };
	final int[] dh = new int[] { 1, 0, -1, 0, 1, -1, 1, -1 };

	boolean inField(int nw, int nh) {
		if (nw < 0 || nw >= W || nh < 0 || nh >= H) {
			return false;
		}
		return true;
	}

	// Yes/No
	static String yesno(boolean f) {
		return yesno(f, "Yes", "No");
	}

	static String yesno(boolean f, String yes, String no) {
		return (f ? yes : no);
	}

	// library
	class FastScanner {
		private final InputStream in;
		private final byte[] buffer = new byte[1024];
		private int ptr = 0;
		private int buflen = 0;

		FastScanner(InputStream in) {
			this.in = in;
		}

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

		public boolean hasNext() {
			while (hasNextByte() && !isPrintableChar(buffer[ptr]))
				ptr++;
			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() {
			long nl = nextLong();
			if (nl < Integer.MIN_VALUE || nl > Integer.MAX_VALUE)
				throw new NumberFormatException();
			return (int) nl;
		}

		public double nextDouble() {
			return Double.parseDouble(next());
		}
	}
}

Measured memory_bytes: 24532