#include <bits/stdc++.h>
using namespace std;
int k, n;
long long curans;
vector <int> h;
bool sorting(pair <int, int> a, pair <int, int> b){
return a.first + a.second < b.first + b.second;
}
int findmedian(vector<pair<int, int>> j){
vector <int> d;
for (int i = 0; i < j.size(); i++){
d.push_back(j[i].first);
d.push_back(j[i].second);
}
d.erase(remove(d.begin(), d.end(), -1), d.end());
sort (d.begin(), d.end());
if (d.size() == 0) return 0;
return (d[d.size() / 2] + d[d.size() / 2 - 1]) / 2;
}
int main(){
long long ans = 0, dans = 0;
int k, n;
ios_base::sync_with_stdio(false);
cin.tie(NULL);
cin >> k >> n;
int a[n*2];
vector <int> z;
vector <pair<int,int>> v;
char b[n], d[n];
for (int i = 0; i < n; i++){
cin >> b[i] >> a[i*2] >> d[i] >> a[i*2+1];
if (b[i] == d[i]){
v.push_back({-1, -1});
z.push_back(-1);
z.push_back(-1);
}
else {
dans++;
v.push_back({a[i*2], a[i*2+1]});
z.push_back(a[i*2]);
z.push_back(a[i*2+1]);
}
if (a[i*2] > a[i*2+1]){
swap(a[i*2], a[i*2+1]);
}
dans += a[i*2+1] - a[i*2];
}
int f;
if (k == 1){
while (k--){
f = findmedian(v);
for (int i = 0; i < n; i++){
if (f >= a[i*2] && f <= a[i*2+1]){
v[i].first = -1;
v[i].second = -1;
}
}
}
for (int i = 0; i < n; i++){
if (b[i] == d[i]){
ans += a[i*2+1] - a[i*2];
}
else{
if (v[i].first == -1){
ans += a[i*2+1] - a[i*2] + 1;
}
else{
if (f < a[i*2]) ans += 1 + a[i*2+1] - a[i*2] + 2 * (a[i*2] - f);
if (f > a[i*2+1]) ans += 1 + a[i*2+1] - a[i*2] + 2 * (f - a[i*2+1]);
}
}
}
}
else{
ans = LLONG_MAX;
int f, g, c;
sort(v.begin(), v.end(), sorting);
vector <pair<int, int>>start(v.begin(), v.begin() + 1);
vector <pair<int, int>>ends(v.begin() + 1, v.end());
for (int N = 1; N <= n; N++){
h = z;
curans = dans;
if (N != 1){
start.push_back(v[N-1]);
ends.erase(ends.begin());
}
f = findmedian(start);
g = findmedian(ends);
for (int i = 0; i < n; i++){
if (f >= a[i*2] && f <= a[i*2+1]){
h[i*2] = -1;
h[i*2+1] = -1;
}
}
for (int i = 0; i < n; i++){
if (g >= a[i*2] && g <= a[i*2+1]){
h[i*2] = -1;
h[i*2+1] = -1;
}
}
int change = 0;
if (N == 1){
for (int i = 0; i < n; i++){
if (b[i] != d[i] && h[i*2] != -1){
if (f < a[i*2]) c = 2 * (a[i*2] - f);
else c = 2 * (f - a[i*2+1]);
if (g < a[i*2]) c = min(2 * (a[i*2] - g), c);
else c = min(2 * (g - a[i*2+1]), c);
}
}
}
else{
for (int i = 0; i < n; i++){
if (b[i] != d[i] && h[i*2] != -1){
if (f < a[i*2]) c = 2 * (a[i*2] - f);
else c = 2 * (f - a[i*2+1]);
if (g < a[i*2]) c = min(2 * (a[i*2] - g), c);
else c = min(2 * (g - a[i*2+1]), c);
}
}
}
ans = min(curans, ans);
}
}
cout << ans;
}
