#![allow(non_snake_case, unused_imports, unused_must_use)]
use std::io::{self, prelude::*};
use std::str;

fn main() {
    let (stdin, stdout) = (io::stdin(), io::stdout());
    let mut scan = Scanner::new(stdin.lock());
    let mut out = io::BufWriter::new(stdout.lock());

    macro_rules! input {
        ($T: ty) => {
            scan.token::<$T>()
        };
        ($T: ty, $N: expr) => {
            (0..$N).map(|_| scan.token::<$T>()).collect::<Vec<_>>()
        };
    }

    let N = input!(usize);
    let M = input!(usize);

    let E = (0..M)
        .map(|_| (input!(usize) - 1, input!(usize) - 1))
        .collect::<Vec<_>>();

    let mut graph = vec![vec![]; 2 * N];

    for (u, v) in E {
        graph[u].push(v);
        graph[v].push(u);
    }

    let mut cnt = 0;

    let mut seen = vec![false; 2 * N];

    for i in 0..2 * N {
        if seen[i] {
            continue;
        }

        let mut c = 0;
        let mut q = std::collections::VecDeque::new();
        q.push_front(i);
        seen[i] = true;
        c += 1;

        while let Some(now) = q.pop_front() {
            for &nxt in graph[now].iter() {
                if !seen[nxt] {
                    seen[nxt] = true;
                    q.push_back(nxt);
                    c += 1;
                }
            }
        }

        //eprintln!("{} {}", i, c);

        if c % 2 != 0 {
            cnt += 1;
        }
    }

    writeln!(out, "{}", cnt / 2);
}

struct Scanner<R> {
    reader: R,
    buf_str: Vec<u8>,
    buf_iter: str::SplitWhitespace<'static>,
}
impl<R: BufRead> Scanner<R> {
    fn new(reader: R) -> Self {
        Self {
            reader,
            buf_str: vec![],
            buf_iter: "".split_whitespace(),
        }
    }
    fn token<T: str::FromStr>(&mut self) -> T {
        loop {
            if let Some(token) = self.buf_iter.next() {
                return token.parse().ok().expect("Failed parse");
            }
            self.buf_str.clear();
            self.reader
                .read_until(b'\n', &mut self.buf_str)
                .expect("Failed read");
            self.buf_iter = unsafe {
                let slice = str::from_utf8_unchecked(&self.buf_str);
                std::mem::transmute(slice.split_whitespace())
            }
        }
    }
}