#include <iostream>
#include <vector>
#include <algorithm>
#include <queue>
using namespace std;
typedef long long ll;
struct Person {
ll s, t;
};
// Mediana yordamida masofalarni hisoblash uchun Priority Queues usuli
struct MedianFinder {
priority_queue<ll> left; // Max-heap
priority_queue<ll, vector<ll>, greater<ll>> right; // Min-heap
ll leftSum = 0, rightSum = 0;
void add(ll val) {
if (left.empty() || val <= left.top()) {
left.push(val); leftSum += val;
} else {
right.push(val); rightSum += val;
}
// Balanslash
if (left.size() > right.size() + 1) {
ll tmp = left.top(); left.pop(); leftSum -= tmp;
right.push(tmp); rightSum += tmp;
} else if (right.size() > left.size()) {
ll tmp = right.top(); right.pop(); rightSum -= tmp;
left.push(tmp); leftSum += tmp;
}
}
ll getCost() {
ll median = left.top();
return (median * (ll)left.size() - leftSum) + (rightSum - median * (ll)right.size());
}
};
int main() {
int K, N;
cin >> K >> N;
ll baseDist = 0;
vector<Person> crossers;
for (int i = 0; i < N; i++) {
char pZ, qZ; ll s, t;
cin >> pZ >> s >> qZ >> t;
if (pZ == qZ) {
baseDist += abs(s - t);
} else {
baseDist += 1; // Daryoni o'tish
crossers.push_back({min(s, t), max(s, t)});
}
}
if (crossers.empty()) {
cout << baseDist << endl; return 0;
}
// K=1 holati
sort(crossers.begin(), crossers.end(), [](Person a, Person b) {
return a.s + a.t < b.s + b.t;
});
int M = crossers.size();
if (K == 1) {
vector<ll> allCoords;
for (auto p : crossers) { allCoords.push_back(p.s); allCoords.push_back(p.t); }
sort(allCoords.begin(), allCoords.end());
ll median = allCoords[M];
ll addCost = 0;
for (ll c : allCoords) addCost += abs(c - median);
cout << baseDist + addCost << endl;
} else {
// K=2 holati uchun Prefiks va Suffiks medianalar
vector<ll> pref(M), suff(M);
MedianFinder mfLeft, mfRight;
for (int i = 0; i < M; i++) {
mfLeft.add(crossers[i].s); mfLeft.add(crossers[i].t);
pref[i] = mfLeft.getCost();
}
for (int i = M - 1; i >= 0; i--) {
mfRight.add(crossers[i].s); mfRight.add(crossers[i].t);
suff[i] = mfRight.getCost();
}
ll minAddCost = pref[M - 1];
for (int i = 0; i < M - 1; i++) {
minAddCost = min(minAddCost, pref[i] + suff[i + 1]);
}
cout << baseDist + minAddCost << endl;
}
return 0;
}
