#include <bits/stdc++.h>
using namespace std;
using ll = long long;
// dynamically solve the optmization problem \min_x \sum_{i=1}^n |x_i-x|
class SlidingMedian {
int64_t suml, sumr;
multiset<int> l, r;
public:
SlidingMedian(): suml{0}, sumr{0}, l{}, r{} {}
void add(int x) {
if (l.empty() || x <= mid()) l.insert(x), suml += x;
else r.insert(x), sumr += x;
normalize();
}
void rem(int x) {
auto it = l.find(x);
if (it != l.end()) suml -= x, l.erase(it);
else r.erase(r.find(x)), sumr -= x;
normalize();
}
int mid() { return *l.rbegin(); }
int64_t opt() {
if (l.empty()) return 0;
int x = mid();
return (1LL * x * l.size() - suml) + (sumr - 1LL * x * r.size());
}
private:
void normalize() {
if (l.size() > r.size() + 1) {
int x = mid();
suml -= x, sumr += x;
l.erase(prev(l.end())), r.insert(x);
} else if (r.size() > l.size()) {
int x = *r.begin();
suml += x, sumr -= x;
l.insert(x), r.erase(r.begin());
}
}
};
int main() {
ios_base::sync_with_stdio(0);
cin.tie(0);
cout.tie(0);
int k, n; cin >> k >> n;
vector<pair<int,int>> p;
vector<int> xs;
ll base_cost = 0;
for (int i = 0; i < n; i++) {
char a, b; int l, r; cin >> a >> l >> b >> r;
if (l > r) swap(l, r);
if (a == b) { base_cost += r - l; continue; }
base_cost++;
p.emplace_back(l, r);
xs.push_back(l), xs.push_back(r);
}
ranges::sort(p, less<int>(), [](auto &&x) { return x.first + x.second; });
SlidingMedian sm1, sm2;
for (int x : xs) sm1.add(x);
ll ans = base_cost + sm1.opt();
if (k == 1) return cout << ans << '\n', 0;
for (auto [l, r] : p) {
sm1.rem(l), sm1.rem(r);
sm2.add(l), sm2.add(r);
ans = min(ans, base_cost + sm1.opt() + sm2.opt());
}
cout << ans << '\n';
}
