#define X first

#define Y second

int board[101][101];

bool vis[101][101];

vector<pair<int, int>> adj[101][101];

int dx[4] = {1, 0, -1, 0};

int dy[4] = {0, 1, 0, -1};

int n, m;

bool OOB(int a, int b) { return a < 1 || a > n || b < 1 || b > n; }

bool is_conn(pair<int, int> nxt) {

for (int dir = 0; dir < 4; dir++) {

int nx = nxt.X + dx[dir];

int ny = nxt.Y + dy[dir];

if (OOB(nx, ny)) continue;

if (vis[nx][ny]) return 1;

}

return 0;

}

int main(void) {

cin >> n >> m;

while (m--) {

int x, y, a, b;

cin >> x >> y >> a >> b;

adj[x][y].push_back({a, b});

}

queue<pair<int, int>> Q;

board[1][1] = 1;

vis[1][1] = 1;

Q.push({1, 1});

while (!Q.empty()) {

auto cur = Q.front();

Q.pop();

for (auto nxt : adj[cur.X][cur.Y]) {

if (vis[nxt.X][nxt.Y]) continue;

if (is_conn(nxt)) {

vis[nxt.X][nxt.Y] = 1;

Q.push({nxt.X, nxt.Y});

}

board[nxt.X][nxt.Y] = 1;

}

for (int dir = 0; dir < 4; dir++) {

int nx = cur.X + dx[dir];

int ny = cur.Y + dy[dir];

if (OOB(nx, ny) || vis[nx][ny] || board[nx][ny] == 0) continue;

vis[nx][ny] = 1;

Q.push({nx, ny});

}

}

int ans = 0;

for (int i = 1; i <= n; i++)

for (int j = 1; j <= n; j++) ans += board[i][j];

cout << ans;

}