# include <bits/stdc++.h>
#pragma GCC optimize("Ofast")
# define f first
# define s second
using namespace std;
const int N = 1e5 + 2;
int n, k, cn, sz = 1, root[N];
long long ans = 1e18, p1[N], s1[N], p2[N], s2[N], ss;
int cnt1[2002][2002], cnt2[2002][2002];
long long sum1[2002][2002], sum2[2002][2002];
vector <int> v, v1, v2;
pair < pair <int, int> , pair <char, char> > a[N];
pair <int, pair <int, int> > b[N];
int main(){
ios_base::sync_with_stdio(0);
cin.tie(0);
cin >> k >> n;
for(int i = 1; i <= n; i ++){
cin >> a[i].s.f >> a[i].f.f >> a[i].s.s >> a[i].f.s;
if(a[i].f.f > a[i].f.s) swap(a[i].f.f, a[i].f.s);
if(a[i].s.f != a[i].s.s) {
cn ++;
v1.push_back(a[i].f.f), v2.push_back(a[i].f.s);
b[cn] = {(a[i].f.f + a[i].f.s + 1), {a[i].f.f, a[i].f.s}};
} else {
ss += abs(a[i].f.s - a[i].f.f);
}
v.push_back(a[i].f.f);
v.push_back(a[i].f.s);
}
v1.push_back(-1e9);
v2.push_back(-1e9);
sort(b + 1, b + cn + 1);
sort(v.begin(), v.end());
v.resize(unique(v.begin(), v.end()) - v.begin());
sort(v1.begin(), v1.end());
sort(v2.begin(), v2.end());
for(int i = 1; i <= cn; i ++){
p1[i] = p1[i - 1] + v1[i];
p2[i] = p2[i - 1] + v2[i];
}
for(int i = cn; i >= 1; i --){
s1[i] = s1[i + 1] + v1[i];
s2[i] = s2[i + 1] + v2[i];
}
int pos = 0, ps = 0;
for(int i = 0; i < v.size(); i ++){
long long res = 0;
int x = v[i];
while(pos + 1 <= cn && v1[pos + 1] <= x) pos ++;
while(ps + 1 <= cn && v2[ps + 1] <= x) ps ++;
res += x * 1ll * pos - p1[pos];
res += x * 1ll * ps - p2[ps];
res += s1[pos + 1] - x * 1ll * (cn - pos);
res += s2[ps + 1] - x * 1ll * (cn - ps);
ans = min(ans, res + cn + ss);
}
if(k == 2){
long long mn = 1e18;
for(int i = 0; i < v.size(); i ++){
for(int j = 1; j <= cn; j ++){
if(b[j].s.f <= v[i])
sum1[i][j] += b[j].s.f, cnt1[i][j] ++;
else
sum2[i][j] += b[j].s.f, cnt2[i][j] ++;
if(b[j].s.s <= v[i])
sum1[i][j] += b[j].s.s, cnt1[i][j] ++;
else
sum2[i][j] += b[j].s.s, cnt2[i][j] ++;
sum1[i][j] += sum1[i][j - 1];
cnt1[i][j] += cnt1[i][j - 1];
sum2[i][j] += sum2[i][j - 1];
cnt2[i][j] += cnt2[i][j - 1];
}
}
for(int i = 0; i < v.size(); i ++){
ps = 0;
for(int j = i + 1; j < v.size(); j ++){
long long res = 0;
int x = (v[i] + v[j] + 1);
while(b[ps + 1].f <= x && ps + 1 <= cn) {
ps ++;
}
res += v[i] * 1ll * cnt1[i][ps] - sum1[i][ps];
res += sum2[i][ps] - v[i] * 1ll * cnt2[i][ps];
res += v[j] * 1ll * (cnt1[j][cn] - cnt1[j][ps]) - (sum1[j][cn] - sum1[j][ps]);
res += (sum2[j][cn] - sum2[j][ps]) - v[j] * 1ll *(cnt2[j][cn] - cnt2[j][ps]) ;
if(mn > res) mn = res;
}
}
ans = min(ans, mn + cn + ss);
}
cout << ans;
// cin.get(); cin.get();
}
/***
2 5
B 0 A 4
B 1 B 3
A 5 B 7
B 2 A 6
B 1 A 7
***/
