// #pragma GCC target("avx2")
#pragma GCC optimize("O3", "unroll-loops")
// #include <bits/extc++.h>
// using namespace __gnu_pbds;
#include <bits/stdc++.h>
using namespace std;
#define int long long
#define double long double
// template <typename T>
// using pbds_set = tree<T, null_type, less<T>, rb_tree_tag, tree_order_statistics_node_update>;
using pii = pair<int, int>;
template<typename T>
using prior = priority_queue<T, vector<T>, greater<T>>;
template<typename T>
using Prior = priority_queue<T>;
#define X first
#define Y second
#define ALL(x) (x).begin(), (x).end()
#define eb emplace_back
#define pb push_back
#define fastIO() ios_base::sync_with_stdio(false); cin.tie(0); cout.tie(0)
#define RANDOM() random_device __rd; \
mt19937 __gen = mt19937(__rd()); \
uniform_int_distribution<int> __dis(0, 1); \
auto rnd = bind(__dis, __gen);
const int INF = 1E18;
const int mod = 1E9 + 7;
struct Citizen {
char p, q;
int s, t;
void Read() {
cin >> p >> s >> q >> t;
}
};
int32_t main() {
fastIO();
int k, n, ans1 = 0;
cin >> k >> n;
vector<Citizen> v;
for (int i = 0; i < n; ++i) {
Citizen tmp; tmp.Read();
if (tmp.s > tmp.t) swap(tmp.s, tmp.t);
ans1 += tmp.t - tmp.s;
if (tmp.p != tmp.q) ++ans1, v.eb(tmp);
}
n = v.size();
if (k == 1) {
int ans2 = INF * (n > 0);
for (int i = 0; i < n; ++i) {
int tmp1 = 0, tmp2 = 0;
for (int j = 0; j < n; ++j) {
if (v[i].s < v[j].s) tmp1 += 2 * (v[j].s - v[i].s);
if (v[i].s > v[j].t) tmp1 += 2 * (v[i].s - v[j].t);
}
for (int j = 0; j < n; ++j) {
if (v[i].t < v[j].s) tmp2 += 2 * (v[j].s - v[i].t);
if (v[i].t > v[j].t) tmp2 += 2 * (v[i].t - v[j].t);
}
ans2 = min({ans2, tmp1, tmp2});
}
cout << ans1+ans2 << "\n";
return 0;
}
return 0;
}
