#include <bits/stdc++.h>
using namespace std;
#define int long long
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() + 1, pv.begin() + pv.size());
if (k == 1) {
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 bridge1, bridge2;
int totans = 1e18;
for (int i = 1; i <= m; i++) {
ans = 0;
bridge1 = v[i];
int idx = m / 2;
vector<int> tmp;
for (int j = 1; j <= (m / 2); j++) {
if (pv[j].first > bridge1) {
idx = j; break;
}
}
for (int j = idx; j <= (m / 2); j++) {
tmp.push_back(pv[j].first);
tmp.push_back(pv[j].second);
}
sort(tmp.begin(), tmp.end());
bridge2 = tmp[(tmp.size()) / 2];
//. cout << bridge1 << " " << bridge2 << "\n";
for (int j = 1; j <= (m / 2); j++) {
int fb, sb;
fb = abs(bridge1 - pv[j].first) + abs(bridge1 - pv[j].second) + 1;
sb = abs(bridge2 - pv[j].first) + abs(bridge2 - pv[j].second) + 1;
ans += min(fb, sb);
}
totans = min(totans, ans);
}
// cout << bridge1 << " " << bridge2 << "\n";
cout << totans + sameside << "\n";
}
return 0;
}
