#include <bits/stdc++.h>
using namespace std;
using ll = long long; 

vector<vector<int>> A;
vector<bool> V;

int dfs(int u) {
  if(V[u]) {
    return 0;
}    
    V[u] = true;
  int size = 1;
  for(auto v : A[u]) {
    size += dfs(v);
  }
  return size;
}

int main() {
  int n, m;
  cin >> n >> m;
  A.resize(2*n);
  V.resize(2*n, false);
  for(int i=0; i<m; i++) {
    int a, b;
    cin >> a >> b;
    a--; b--; 
    A[a].push_back(b);
    A[b].push_back(a);
  }
  int p = 0;
  for (int i=0; i<2*n; i++) {
    if(!V[i]) {
      int size = dfs(i);
      if(size%2!=0) {
        p++;
      }  
    }
  }
  cout << p/2 << endl;
}