#include <iostream>
#include <vector>
#include <algorithm>
#include <cstdio>
#include <cstring>
#include <set>
#include <cassert>
using namespace std;
struct Balancer
{
multiset<int> lef, rig;
int cntLef, cntRig;
int64_t sumLef, sumRig;
Balancer()
{
lef.clear(), rig.clear();
cntLef = 0, cntRig = 0;
sumLef = 0, sumRig = 0;
}
void add(int l, int r)
{
// cout << "add " << l << ' ' << r << endl;
l = l << 1, r = r << 1 | 1;
int mid = (!lef.empty() ? *lef.rbegin() : 0);
if (l <= mid) lef.insert(l);
else rig.insert(l), sumRig += l / 2, ++cntRig;
if (r <= mid) lef.insert(r), sumLef += r / 2, ++cntLef;
else rig.insert(r);
while (((int) rig.size()) - ((int) lef.size()) > 1) {
int x = *rig.begin();
rig.erase(rig.begin());
lef.insert(lef.end(), x);
if (x & 1) sumLef += x / 2, ++cntLef;
else sumRig -= x / 2, --cntRig;
}
while (((int) lef.size()) - ((int) rig.size()) > 1) {
int x = *lef.rbegin();
lef.erase(prev(lef.end()));
rig.insert(rig.begin(), x);
if (x & 1) sumLef -= x / 2, --cntLef;
else sumRig += x / 2, ++cntRig;
}
}
int64_t get()
{
if (lef.empty() && rig.empty()) return 0;
int64_t mid = (lef.empty() ? *rig.begin() : *lef.rbegin());
// cout << "get " << (cntLef - cntRig) * mid - sumLef + sumRig << endl;
return (cntLef - cntRig) * mid - sumLef + sumRig;
}
};
int main()
{
ios_base::sync_with_stdio(0); cin.tie(0);
int K, M;
cin >> K >> M;
vector<pair<int, int>> vec;
int64_t offset = 0;
while (M--) {
char cA, cB;
int valA, valB;
cin >> cA >> valA >> cB >> valB;
if (valA > valB) swap(valA, valB);
offset += valB - valA;
if (cA != cB) vec.emplace_back(valA, valB);
}
M = (int) vec.size();
offset += M;
sort(vec.begin(), vec.end(), [&](pair<int, int> p, pair<int, int> q) { return p.first + p.second < q.first + q.second; });
if (M == 0) return cout << offset << endl, 0;
vector<int64_t> pref(M, 0);
Balancer bal;
for (int i = 0; i < M; ++i) {
bal.add(vec[i].first, vec[i].second);
pref[i] = bal.get();
}
int64_t ans = pref[M - 1];
if (K == 1) return cout << offset + 2 * ans << endl, 0;
bal = Balancer();
for (int i = M - 1; i > 0; --i) {
bal.add(vec[i].first, vec[i].second);
ans = min(ans, bal.get() + pref[i - 1]);
}
cout << offset + 2 * ans << endl;
}
