#include <bits/stdc++.h>
using namespace std;
const int DIM = 100005;
long long lst1[DIM], lst2[DIM];
vector<pair<int, int>> arr;
void insert(auto &lef, auto &rig, long long &lsum, long long &rsum, int x) {
if (!lef.size() or x <= lef.top()) {
lsum += x; lef.push(x); }
else {
rsum += x; rig.push(x); } }
void balance(auto &lef, auto &rig, long long &lsum, long long &rsum) {
while ((int) rig.size() - (int) lef.size() > 1) {
lsum += rig.top(); rsum -= rig.top(); lef.push(rig.top()); rig.pop(); }
while ((int) lef.size() - (int) rig.size() > 1) {
rsum += lef.top(); lsum -= lef.top(); rig.push(lef.top()); lef.pop(); } }
void solve(long long lst[DIM]) {
long long lsum = 0, rsum = 0;
priority_queue<int, vector<int>, less<int>> lef;
priority_queue<int, vector<int>, greater<int>> rig;
for (int i = 1; i <= (int) arr.size(); ++i) {
insert(lef, rig, lsum, rsum, arr[i - 1].first);
insert(lef, rig, lsum, rsum, arr[i - 1].second);
balance(lef, rig, lsum, rsum);
lst[i] = 1LL * lef.top() * (lef.size() - rig.size()) - lsum + rsum; } }
int main(void) {
#ifdef HOME
freopen("bridge.in", "r", stdin);
freopen("bridge.out", "w", stdout);
#endif
int k, n; cin >> k >> n;
long long ans = 0;
for (int i = 1; i <= n; ++i) {
char c1, c2; int p1, p2;
cin >> c1 >> p1 >> c2 >> p2;
if (c1 == c2) {
ans += abs(p2 - p1); }
else {
arr.emplace_back(min(p1, p2), max(p1, p2)); } }
sort(arr.begin(), arr.end(),
[](const pair<int, int> &p1, const pair<int, int> &p2) {
return p1.first + p1.second < p2.first + p2.second; });
solve(lst1); reverse(arr.begin(), arr.end()); solve(lst2);
long long cst = (1LL << 50);
for (int i = 0; i <= (int) arr.size(); ++i) {
cst = min(cst, lst1[i] + lst2[arr.size() - i]); }
if (k == 1) {
cst = lst1[arr.size()]; }
cout << ans + arr.size() + cst << endl;
return 0; }
