#include <algorithm>
#include <array>
#include <bitset>
#include <cassert>
#include <chrono>
#include <climits>
#include <cmath>
#include <complex>
#include <cstring>
#include <functional>
#include <iomanip>
#include <iostream>
#include <map>
#include <numeric>
#include <queue>
#include <random>
#include <set>
#include <vector>
using namespace std;

#define ll long long
#define forn(i, s, n) for (int i = s; i < n; i++)
#define bforn(i, s) for (int i = s; i >= 0; i--)
// for pairs
#define s second
#define f first
const int M = 2e5 + 1;
const char nl = '\n';

int g[102][102];
map<pair<int, int>, vector<pair<int, int> > > sw;
bool vis[102][102];
int n;

void ff(int x, int y){
    if (vis[x][y] || g[x][y] == 0 || g[x][y] == -1) return;
    vis[x][y] = true;
    g[x][y] = 1;
    for (auto i : sw[{x,y}]){
        int a = i.f;
        int b = i.s;
        if (vis[a][b]) continue;
        g[a][b] = 1;
        if (vis[a - 1][b] == 1 || vis[a + 1][b] == 1 || vis[a][b + 1] == 1 || vis[a][b - 1] == 1) ff(a, b);
    }
    ff(x + 1, y);
    ff(x - 1, y);
    ff(x, y + 1);
    ff(x, y - 1);
}
void solve(){
    int m; cin >>n>>m;
    for (int i = 0; i < m; i++){
        int a,b,c,d; cin >> a>>b>>c>>d;
        sw[{a,b}].push_back({c,d});
    }
    for (int i = 0; i < 102; i++){
        for (int j = 0; j < 102; j++){
            if (i == 0 || j == 0 || j == 101 || i == 101) g[i][j] = -1;
            else g[i][j] = 0;
            vis[i][j] = false;
        }
    }
    g[1][1] = 1;
    ff(1,1);
    int ans = 0;
    for (int i = 0; i <= n; i++){
        for (int j = 0; j <= n; j++){
            if (g[i][j] == 1) ans++;
        }
    }
    cout << ans << nl;
}
// if you are unsure of how to do a problem by hand
// the solution is most likely somewhat brute force (i.e binsearch)
// if input is limited to 0-9 or a-z, usually you will loop through all combinations
// of letters or numbers
// constructive problems : start with 1 when constructing
// :%y+ to copy all lines
// rearrange math expressions
// difference array? (a[i] - b[i])
// debugging : reread the problem statement-every word is important!
// debugging : print important variables!
// think brute force sol first
int main(){
    ios::sync_with_stdio(false);
    cin.tie(nullptr);
    cout.tie(nullptr);
    freopen("lightson.in", "r", stdin);
    freopen("lightson.out", "w", stdout);
    solve();
}