#include <bits/stdc++.h>
// #include <ext/pb_ds/assoc_container.hpp>
// #include <ext/pb_ds/trie_policy.hpp>
// #include <ext/rope>
using namespace std;
// using namespace __gnu_cxx;
// using namespace __gnu_pbds;
void Hollwo_Pelw();
signed main(){
#ifndef hollwo_pelw_local
if (fopen(".inp", "r"))
assert(freopen(".inp", "r", stdin)), assert(freopen(".out", "w", stdout));
#else
using namespace chrono;
auto start = steady_clock::now();
#endif
cin.tie(0), cout.tie(0) -> sync_with_stdio(0);
int testcases = 1;
// cin >> testcases;
for (int test = 1; test <= testcases; test++){
// cout << "Case #" << test << ": ";
Hollwo_Pelw();
}
#ifdef hollwo_pelw_local
auto end = steady_clock::now();
cout << "\nExecution time : " << duration_cast<milliseconds> (end - start).count() << "[ms]" << endl;
#endif
}
const int N = 1e5 + 5;
int n, k;
long long pre[N], suf[N], extra;
vector<pair<int, int>> seg;
struct median_pq {
priority_queue<int> pql, pqr;
long long suml = 0, sumr = 0;
inline void clear() {
suml = sumr = 0;
while (!pql.empty()) pql.pop();
while (!pqr.empty()) pqr.pop();
}
inline void push(int a, int b) {
pql.push(+a), suml += a;
pqr.push(-b), sumr += b;
if (pql.top() > - pqr.top()) {
a = pql.top();
b = pqr.top();
pql.pop();
pqr.pop();
pql.push(-b);
pqr.push(-a);
suml = suml - a - b;
sumr = sumr + a + b;
}
}
inline long long get() {
return sumr - suml;
}
} pq;
void Hollwo_Pelw(){
cin >> k >> n;
for (int i = 0; i < n; i++) {
char ta, tb; int pa, pb;
cin >> ta >> pa >> tb >> pb;
if (pa > pb) swap(pa, pb);
if (ta == tb) {
extra += abs(pa - pb);
}
else {
seg.emplace_back(pa, pb);
}
}
n = seg.size(), extra += n;
sort(seg.begin(), seg.end(), [&](const pair<int, int> &a, const pair<int, int> &b){
return a.first + a.second < b.first + b.second;
});
pq.clear();
for (int i = 0; i < n; i++) {
pq.push(seg[i].first, seg[i].second);
pre[i + 1] = pq.get();
// cout << "add " << seg[i].first << ' ' << seg[i].second << '\n' << pq.get() << '\n';
}
pq.clear();
for (int i = n; i --; ) {
pq.push(seg[i].first, seg[i].second);
suf[i + 1] = pq.get();
// cout << "add " << seg[i].first << ' ' << seg[i].second << '\n' << pq.get() << '\n';
}
long long res = pre[n];
if (k == 1) {
cout << res + extra << '\n';
return ;
}
for (int i = 1; i <= n; i++)
res = min(res, pre[i - 1] + suf[i]);
cout << res + extra << '\n';
}
