#include <bits/stdc++.h>
using namespace std;
typedef long long ll;
typedef pair<int,int> pii;
# define im INT_MAX
# define umap unordered_map
# define uset unordered_set
# define f first
# define s second
# define pq priority_queue
# define pb push_back
# define ins insert
# define INF LLONG_MAX
#define int long long
int n, m;
map<pii,vector<pii>> switches;
int on[102][102]; bool visited[102][102];


void floodfill(){
    // cout << "i: " << i << ", j: " << j << '\n';
    queue<pii> q; q.push({1,1});

    while (q.size()){
        // cout << "queue: "; printQueuePair(q); cout << '\n';
        int i=q.front().f; int j=q.front().s; q.pop();
        // cout << "i: " << i << ", j: " << j << '\n';
        for (pii room : switches[{i,j}]){ // switch on everything from the current room
            if (!on[room.f][room.s]){
                on[room.f][room.s] = true;
                if (visited[room.f+1][room.s] || visited[room.f-1][room.s] || visited[room.f][room.s+1] || visited[room.f][room.s-1]){
                    visited[room.f][room.s] = true;
                    q.push(room);
                }
            }
        }
        if (on[i+1][j] && !visited[i+1][j]){ // if (i+1,j) is in range, on, and unvisited
            visited[i+1][j] = true; // mark as visited
            q.push({i+1,j}); // queue it
        }
        if (on[i-1][j] && !visited[i-1][j]){
            visited[i-1][j] = true;
            q.push({i-1,j});
        }
        if (on[i][j+1] && !visited[i][j+1]){
            visited[i][j+1] = true;
            q.push({i,j+1});
        }
        if (on[i][j-1] && !visited[i][j-1]){
            visited[i][j-1] = true;
            q.push({i,j-1});
        }
    }


}

main(){
    ifstream cin("lightson.in");
    ofstream cout("lightson.out");

    cin >> n >> m;
    for (int i=0; i<m; i++){
        int x, y, a, b; cin >> x >> y >> a >> b;
        switches[{x,y}].pb({a,b});
    }

    // printPairContPairMap(switches);
    on[1][1] = true;
    visited[1][1] = true;
    floodfill();

    // cout << "on:\n"; print2dArray(on,n+1,n+1);
    // cout << "visited:\n"; print2dArray(visited,n+1,n+1);

    int lit_rooms = 0;
    for (int i=1; i<=n; i++){
        for (int j=1; j<=n; j++){
            lit_rooms += on[i][j];
        }
    }

    cout << lit_rooms << '\n';


    return 0;
}