#include <bits/stdc++.h>
using namespace std;
using ll = long long;
int main() {
ios::sync_with_stdio(false); cin.tie(nullptr);
int K, n;
cin >> K >> n;
ll sm = 0;
vector<vector<int>> v;
for (int i = 0; i < n; i++) {
char p, q;
int s, t;
cin >> p >> s >> q >> t;
if (p == q) sm += abs(t - s);
else v.push_back({s + t, s, t});
}
if (v.empty()) return cout << sm, 0;
sm += (int)v.size();
if (K == 1) {
vector<int> u;
for (auto i : v) u.insert(u.end(), {i[1], i[2]});
sort(u.begin(), u.end());
for (int j = 0; j < (int)u.size(); j++) sm += (j < (int)u.size() >> 1 ? -1 : 1) * u[j];
return cout << sm, 0;
}
sort(v.begin(), v.end());
ll ss1 = 0, ss2 = 0, st1 = 0, st2 = 0;
multiset<int> s1, s2, t1, t2;
auto g = [&]() {
if ((int)s1.size() > (int)s2.size() + 1) {
ss2 += *--s1.end(); ss1 -= *--s1.end();
s2.insert(*--s1.end()); s1.erase(--s1.end());
}
if ((int)s2.size() > (int)s1.size() + 1) {
ss1 += *s2.begin(); ss2 -= *s2.begin();
s1.insert(*s2.begin()); s2.erase(s2.begin());
}
if ((int)t1.size() > (int)t2.size() + 1) {
st2 += *--t1.end(); st1 -= *--t1.end();
t2.insert(*--t1.end()); t1.erase(--t1.end());
}
if ((int)t2.size() > (int)t1.size() + 1) {
st1 += *t2.begin(); st2 -= *t2.begin();
t1.insert(*t2.begin()); t2.erase(t2.begin());
}
};
ss1 = v[0][1] + v[0][2];
s1.insert({v[0][1], v[0][2]});
for (int i = 1; i < (int)v.size(); i++) {
for (auto k : {v[i][1], v[i][2]}) {
if (t2.empty() || k < *t2.begin()) {
st1 += k; t1.insert(k);
}
else {
st2 += k; t2.insert(k);
}
g();
}
}
ll mn = LLONG_MAX;
for (int i = 1; i < (int)v.size(); i++) {
mn = min(mn, (ll)s1.size() * *--s1.end() - ss1 + ss2 - (ll)s2.size() * *--s1.end() + (ll)t1.size() * *--t1.end() - st1 + st2 - (ll)t2.size() * *--t1.end());
for (auto k : {v[i][1], v[i][2]}) {
if (s2.empty() || k < *s2.begin()) {
ss1 += k; s1.insert(k);
}
else {
ss2 += k; s2.insert(k);
}
if (t1.find(k) != t1.end()) {
st1 -= k; t1.erase(t1.find(k));
}
else {
st2 -= k; t2.erase(t2.find(k));
}
g();
}
}
cout << sm + mn;
}
