#include <bits/stdc++.h>
using namespace std;
//Die kürzeste Distanz von einer Person, die in der gleichen Zone lebt
//und zur Arbeit geht, kann sich durch den Brückenbau nicht ändern.
multiset<int> low, high;
long long lowSum, highSum;
void insert(int x) {
if (low.empty() || x <= *low.rbegin()) {
low.insert(x);
lowSum += x;
} else {
high.insert(x);
highSum += x;
}
if (low.size() > high.size() + 1) {
highSum += *low.rbegin();
lowSum -= *prev(low.end());
high.insert(*low.rbegin());
low.erase(prev(low.end()));
} else if (high.size() > low.size()) {
lowSum += *high.begin();
highSum -= *high.begin();
low.insert(*high.begin());
high.erase(high.begin());
}
}
int main() {
ios_base::sync_with_stdio(false);
cin.tie(nullptr);
low.clear();
high.clear();
lowSum = 0;
highSum = 0;
int K, N;
cin >> K >> N;
long long sameZone = 0;
vector<pair<int, int>> citizens; //S T
citizens.emplace_back(0, 0);
for (int i = 0; i<N; i++) {
char p, q;
int s, t;
cin >> p >> s >> q >> t;
if (p == q) {
sameZone += abs(s-t);
} else {
citizens.emplace_back(s, t);
}
}
sort(citizens.begin(), citizens.end(), [&](const pair<int, int> &p1, const pair<int, int> &p2) {
return p1.first + p1.second < p2.first + p2.second;
});
int n = citizens.size()-1;
sameZone += n;
vector<long long> prefix(n+1);
for (int i = 1; i<=n; i++) {
insert(citizens[i].first);
insert(citizens[i].second);
prefix[i] = highSum-lowSum;
}
long long answer = prefix[n];
if (K == 2) {
low.clear();
high.clear();
lowSum = 0;
highSum = 0;
for (int i = n; i>=1; i--) {
insert(citizens[i].first);
insert(citizens[i].second);
answer = min(answer, highSum - lowSum + prefix[i - 1]);
}
}
cout << sameZone + answer;
}
