#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];
int lps[N], lss[N], rps[N], rss[N], lpcnt[N], lscnt[N], rpcnt[N], rscnt[N];
bool cmp(pair<int, int> x, pair<int, int> y) {
return x.first + x.second < y.first + y.second;
}
void precompute(vector<pair<int, int> > pv) {
int nn;
pq<int> below; pq<int, vector<int>, greater<int> > above;
int ls = 0, rs = 0;
for (int i = 1; i < pv.size(); i++) {
int n = pv[i].first;
if (below.empty()) {
below.push(n);
nn = n;
ls += n;
} else if (above.empty()) {
above.push(n); pref[i] = below.top();
nn = (above.top() + below.top()) / 2;
if (above.top() < below.top()) {
int tmp = below.top();
int tmp2 = above.top();
below.pop(); below.push(tmp2);
above.pop(); above.push(tmp);
rs += n;
swap(ls, rs);
} else {
rs += n;
}
} else {
if (n <= nn) {
below.push(n);
ls += n;
} else {
above.push(n);
rs += n;
}
if (sz(below) > sz(above) + 1) {
int tmp = below.top();
below.pop();
above.push(tmp);
ls -= tmp; rs += tmp;
} else if (sz(below) < sz(above)) {
int tmp = above.top();
above.pop();
below.push(tmp);
ls += tmp; rs -= tmp;
}
nn = below.top();
}
n = pv[i].second;
if (below.empty()) {
below.push(n);
nn = n;
ls += n;
} else if (above.empty()) {
above.push(n); pref[i] = below.top();
nn = (above.top() + below.top()) / 2;
if (above.top() < below.top()) {
int tmp = below.top();
int tmp2 = above.top();
below.pop(); below.push(tmp2);
above.pop(); above.push(tmp);
rs += n;
swap(ls, rs);
} else {
rs += n;
}
} else {
if (n <= nn) {
below.push(n);
ls += n;
} else {
above.push(n);
rs += n;
}
if (sz(below) > sz(above) + 1) {
int tmp = below.top();
below.pop();
above.push(tmp);
ls -= tmp; rs += tmp;
} else if (sz(below) < sz(above)) {
int tmp = above.top();
above.pop();
below.push(tmp);
ls += tmp; rs -= tmp;
}
nn = below.top();
pref[i] = nn;
}
lps[i] = ls; rps[i] = rs;
lpcnt[i] = below.size(); rpcnt[i] = above.size();
}
ls = 0; rs = 0;
while (below.size()) below.pop();
while (above.size()) above.pop();
for (int i = pv.size() - 1; i >= 1; i--) {
int n = pv[i].first;
if (below.empty()) {
below.push(n);
nn = n;
ls += n;
} else if (above.empty()) {
above.push(n); suff[i] = below.top();
nn = (above.top() + below.top()) / 2;
if (above.top() < below.top()) {
int tmp = below.top();
int tmp2 = above.top();
below.pop(); below.push(tmp2);
above.pop(); above.push(tmp);
rs += n;
swap(ls, rs);
} else {
rs += n;
}
} else {
if (n <= nn) {
below.push(n);
ls += n;
} else {
above.push(n);
rs += n;
}
if (sz(below) > sz(above) + 1) {
int tmp = below.top();
below.pop();
above.push(tmp);
ls -= tmp; rs += tmp;
} else if (sz(below) < sz(above)) {
int tmp = above.top();
above.pop();
below.push(tmp);
ls += tmp; rs -= tmp;
}
nn = below.top();
}
n = pv[i].second;
if (below.empty()) {
below.push(n);
nn = n;
ls += n;
} else if (above.empty()) {
above.push(n); suff[i] = below.top();
nn = (above.top() + below.top()) / 2;
if (above.top() < below.top()) {
int tmp = below.top();
int tmp2 = above.top();
below.pop(); below.push(tmp2);
above.pop(); above.push(tmp);
rs += n;
swap(ls, rs);
} else {
rs += n;
}
} else {
if (n <= nn) {
below.push(n);
ls += n;
} else {
above.push(n);
rs += n;
}
if (sz(below) > sz(above) + 1) {
int tmp = below.top();
below.pop();
above.push(tmp);
ls -= tmp; rs += tmp;
} else if (sz(below) < sz(above)) {
int tmp = above.top();
above.pop();
below.push(tmp);
ls += tmp; rs -= tmp;
}
nn = below.top();
suff[i] = nn;
}
lss[i] = ls; rss[i] = rs;
lscnt[i] = below.size(); rscnt[i] = above.size();
}
}
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);
precompute(pv);
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 = (m / 2);
ans += (lpcnt[i - 1] * pref[i - 1] - lps[i - 1]);
ans += (rps[i - 1] - pref[i - 1] * rpcnt[i - 1]);
ans += (lscnt[i] * suff[i] - lss[i]);
ans += (rss[i] - suff[i] * rscnt[i]);
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
*/
