#include <bits/stdc++.h>
using namespace std;
class IO {
  static const int bufSize = 1 << 18;
  char inBuf[bufSize], outBuf[bufSize];
  char *ip1 = inBuf, *ip2 = inBuf;
  int goodReadBit = 0, op1 = -1, op2 = bufSize - 1;
  template <typename T>
  __inline__ __attribute__((always_inline)) void __RI(T& x) {
    int ch = gc(), neg = 1;
    x = 0;
    for (; !(isdigit(ch) || ch == '-' || ch == EOF); ch = gc())
      ;
    if (ch == EOF) {
      goodReadBit = 0;
      return;
    }
    if (ch == '-') neg = -1, ch = gc();
    for (; isdigit(ch); ch = gc()) x = x * 10 + (ch - 48) * neg;
  }
  template <typename T>
  __inline__ __attribute__((always_inline)) void __RC(T& x) {
    unsigned char ch;
    while (isspace(ch = gc()))
      ;
    x = ch;
  }
  __inline__ __attribute__((always_inline)) void __RS(string& x) {
    char ch;
    x.clear();
    for (ch = gc(); isspace(ch); ch = gc())
      ;
    if (ch == EOF) {
      goodReadBit = 0;
      return;
    }
    for (; !isspace(ch); ch = gc()) x.push_back(ch);
  }

 public:
  __inline__ __attribute__((always_inline)) int gc() {
    return ip1 == ip2 && (ip2 = (ip1 = inBuf) + fread(inBuf, 1, bufSize, stdin),
                          ip1 == ip2)
               ? EOF
               : *ip1++;
  }
  __inline__ __attribute__((always_inline)) IO& R(char& x) {
    __RC(x);
    return (*this);
  }
  __inline__ __attribute__((always_inline)) IO& R(unsigned char& x) {
    __RC(x);
    return (*this);
  }
  __inline__ __attribute__((always_inline)) IO& R(string& x) {
    __RS(x);
    return (*this);
  }
  template <typename T1, typename T2>
  __inline__ __attribute__((always_inline)) IO& R(pair<T1, T2>& x) {
    R(x.first), R(x.second);
    return (*this);
  }
  template <typename T>
  __inline__ __attribute__((always_inline)) IO& R(vector<T>& x) {
    for (auto& i : x) R(i);
    return (*this);
  }
  template <typename T, typename... Args>
  __inline__ __attribute__((always_inline)) IO& RA(T* a, int n) {
    for (int i = 0; i < n; ++i) R(a[i]);
    return (*this);
  }
  template <typename T, typename... Args>
  __inline__ __attribute__((always_inline)) IO& R(T& x, Args&... args) {
    R(x), R(args...);
    return (*this);
  }
  template <typename T, typename... Args>
  __inline__ __attribute__((always_inline)) IO& RA(T* a, int n, Args... args) {
    for (int i = 0; i < n; ++i) RA(a[i], args...);
    return (*this);
  }
  template <typename T>
  __inline__ __attribute__((always_inline)) IO& R(T& x) {
    static_assert(is_integral<T>::value, "Unsupported types");
    if (is_integral<T>::value) __RI(x);
    return (*this);
  }

 private:
  char space = ' ';
  template <typename T>
  __inline__ __attribute__((always_inline)) void __WI(T x) {
    static char buf[64];
    static int len = -1;
    if (x >= 0) {
      do {
        buf[++len] = x % 10 + 48, x /= 10;
      } while (x);
    } else {
      pc('-');
      do {
        buf[++len] = -(x % 10) + 48, x /= 10;
      } while (x);
    }
    while (len >= 0) {
      pc(buf[len]), --len;
    }
  }

 public:
  __inline__ __attribute__((always_inline)) void pc(const char& x) {
    if (op1 == op2) flush();
    outBuf[++op1] = x;
  }
  __inline__ __attribute__((always_inline)) void flush() {
    fwrite(outBuf, 1, op1 + 1, stdout), op1 = -1;
  }
  __inline__ __attribute__((always_inline)) IO& W(const char& x) {
    pc(x);
    return (*this);
  }
  __inline__ __attribute__((always_inline)) IO& W(const char* x) {
    while (*x != '\0') pc(*(x++));
    return (*this);
  }
  __inline__ __attribute__((always_inline)) IO& W(const string& x) {
    W(x.c_str());
    return (*this);
  }
  template <typename T>
  __inline__ __attribute__((always_inline)) IO& W(const vector<T>& x) {
    for (auto& i : x) WS(i);
    WL();
    return (*this);
  }
  __inline__ __attribute__((always_inline)) IO& WL() {
    W('\n');
    return (*this);
  }
  template <typename T1, typename T2>
  __inline__ __attribute__((always_inline)) IO& W(const pair<T1, T2>& x) {
    WS(x.first), W(x.second);
    return (*this);
  }
  template <typename T>
  __inline__ __attribute__((always_inline)) IO& WL(const T& x) {
    W(x), W('\n');
    return (*this);
  }
  __inline__ __attribute__((always_inline)) IO& WS() {
    W(' ');
    return (*this);
  }
  template <typename T>
  __inline__ __attribute__((always_inline)) IO& WS(const T& x) {
    W(x), W(space);
    return (*this);
  }
  template <typename T>
  __inline__ __attribute__((always_inline)) IO& WA(T* a, int n) {
    for (int i = 0; i < n; i++) WS(a[i]);
    WL();
    return (*this);
  }
  template <typename T, typename... Args>
  __inline__ __attribute__((always_inline)) IO& W(const T& x,
                                                  const Args&... args) {
    W(x), W(space), W(args...);
    return (*this);
  }
  template <typename... Args>
  __inline__ __attribute__((always_inline)) IO& WL(const Args&... args) {
    W(args...), W('\n');
    return (*this);
  }
  template <typename T, typename... Args>
  __inline__ __attribute__((always_inline)) IO& WA(T* a, int n, Args... args) {
    for (int i = 0; i < n; i++) WA(a[i], args...);
    return (*this);
  }
  template <typename T>
  __inline__ __attribute__((always_inline)) IO& W(const T& x) {
    static_assert(is_integral<T>::value, "Unsupported types");
    if (is_integral<T>::value) __WI(x);
    return (*this);
  }
  template <typename T>
  __inline__ __attribute__((always_inline)) IO& operator>>(T& x) {
    R(x);
    return (*this);
  }
  template <typename T>
  __inline__ __attribute__((always_inline)) IO& operator<<(const T& x) {
    W(x);
    return (*this);
  }
  IO() {}
} io;
void EXIT(int code) { io.flush(), exit(code); }
const int8_t INFC = 0x3f;
const int16_t INFS = 0x3f3f;
const int32_t INF = 0x3f3f3f3f;
const int64_t INFL = 0x3f3f3f3f3f3f3f3fLL;
const int MAXN = 5e3;
vector<int> G[MAXN];
unordered_set<int> nG[MAXN];
struct UF {
  int par[MAXN];
  void init(int n) {
    for (int i = 0; i < n; i++) par[i] = i;
  }
  int find(int x) { return par[x] == x ? x : par[x] = find(par[x]); }
  void unite(int x, int y) {
    if ((x = find(x)) == (y = find(y))) return;
    par[x] = y;
  }
} uf;
namespace BiConnected {
int dfn[MAXN], low[MAXN], vis[MAXN], order = 0;
void dfs(int u, int p) {
  dfn[u] = order++;
  low[u] = dfn[u];
  vis[u] = 1;
  for (int v : G[u]) {
    if (v == p) continue;
    if (vis[v])
      low[u] = min(low[u], dfn[v]);
    else {
      dfs(v, u);
      low[u] = min(low[u], low[v]);
      if (dfn[u] >= low[v]) uf.unite(u, v);
    }
  }
}
}  // namespace BiConnected
pair<int, int> bfs(int s) {
  unordered_set<int> vis;
  queue<pair<int, int>> q;
  q.emplace(s, 1);
  vis.insert(s);
  int furthestNode = -1, maxLength = -1;
  while (!q.empty()) {
    auto [u, step] = q.front();
    q.pop();
    if (step > maxLength) maxLength = step, furthestNode = u;
    for (auto v : G[u]) {
      if (vis.count(v)) continue;
      vis.insert(v);
      q.emplace(v, step + 1);
    }
  }
  return {furthestNode, maxLength};
}
int leaveNum[MAXN], nodeNum[MAXN], biSize[MAXN], vis[MAXN];
void dfs(int u, int p, int c) {
  nodeNum[c]++;
  vis[u] = 1;
  bool flg = 0;
  for (auto v : G[u]) {
    if (v == p) continue;
    dfs(v, u, c);
    flg = 1;
  }
  if (!flg) leaveNum[c]++;
}
int main() {
  int n, m;
  io >> n >> m;
  for (int i = 0; i < m; i++) {
    int x, y;
    io >> x >> y;
    --x, --y;
    G[x].push_back(y);
    G[y].push_back(x);
  }
  uf.init(n);
  int numberOfTree = 0;
  for (int i = 0; i < n; i++)
    if (!BiConnected::vis[i]) BiConnected::dfs(i, -1), numberOfTree++;
  for (int i = 0; i < n; i++) biSize[uf.find(i)]++;
  int ans = 0;
  for (int i = 0; i < n; i++) ans += max(0, biSize[i] - 1);
  for (int u = 0; u < n; u++)
    for (auto v : G[u])
      if (uf.find(u) != uf.find(v)) nG[uf.find(u)].insert(uf.find(v));
  for (int i = 0; i < n; i++) G[i].assign(nG[i].begin(), nG[i].end());
  for (int i = 0; i < n; i++)
    if (!vis[i] && G[i].size() > 1) {
      dfs(i, -1, i);
      if (nodeNum[i] == 1 || nodeNum[i] == 2) continue;
      auto t = bfs(i);
      t = bfs(t.first);
      ans += nodeNum[i] - leaveNum[i] - t.second + 2;
    }
  io.WL(ans + numberOfTree - 1);
  EXIT(0);
}
