#include <bits/stdc++.h>
using namespace std;
#define int long long
#define N 100005
#define sz(x) x.size()
#define pq priority_queue
int pref[N], suff[N];
bool cmp(pair<int, int> x, pair<int, int> y) {
return x.first + x.second < y.first + y.second;
}
signed main() {
ios::sync_with_stdio(0); cin.tie(0);
int sameside = 0, k, n, m = 0, ans = 0; cin >> k >> n;
vector<pair<int, int> > pv; pv.push_back({0, 0});
vector<int> v(2 * n + 5);
for (int i = 1; i <= n; i++) {
char p, q; int s, t; cin >> p >> s >> q >> t;
if (p == q) sameside += abs(s - t);
else {
if (s > t) swap(s, t);
m++; v[m] = s;
m++; v[m] = t;
pv.push_back({s, t});
}
}
sort(pv.begin(), pv.end(), cmp);
if (k == 1 || m == 2) {
sort(v.begin() + 1, v.begin() + m + 1);
int bridge = v[(m + 1) / 2];
for (int i = 1; i <= m; i += 2) {
ans += abs(bridge - v[i]) + abs(bridge - v[i + 1]) + 1;
}
cout << ans + sameside << "\n";
} else {
int mn = 1e18;
for (int i = 2; i <= (m / 2); i++) {
ans = 0;
vector<int> A, B;
for (int j = 1; j <= i - 1; j++) {
A.push_back(pv[j].first);
A.push_back(pv[j].second);
}
for (int j = i; j <= (m / 2); j++) {
B.push_back(pv[j].first);
B.push_back(pv[j].second);
}
sort(A.begin(), A.end());
sort(B.begin(), B.end());
int bridge1 = A[A.size() / 2];
int bridge2 = B[B.size() / 2];
for (int j = 1; j <= i - 1; j++) {
ans += abs(bridge1 - pv[j].first) + abs(bridge1 - pv[j].second) + 1;
}
for (int j = i; j <= (m / 2); j++) {
ans += abs(bridge2 - pv[j].first) + abs(bridge2 - pv[j].second) + 1;
}
mn = min(mn, ans);
}
if (m == 0) mn = 0;
cout << mn + sameside << "\n";
}
return 0;
}
/*
2 7
B 1 A 0
A 0 B 0
B 1 B 1
B 1 A 1
B 0 A 1
B 1 A 0
B 0 A 1
*/
