/// adil sultanov | vonat1us
#pragma GCC optimize("O3")
//#pragma comment(linker, "/STACK:36777216")
#include<bits/stdc++.h>
#define x first
#define y second
#define pb push_back
#define sz(x) (int) x.size()
#define all(z) (z).begin(), (z).end()
using namespace std;
using ll = long long;
using pii = pair<int, int>;
const int MOD = 1e9 + 7;
const int INF = 1e9 + 1e2;
void fin() {
#ifdef AM
freopen(".in", "r", stdin);
#endif
}
const bool flag = 0;
const int N = 1e5+10;
void one(vector<int> all, vector<pii> v, ll ans) {
int n = sz(v);
sort(all(all));
//all.erase(unique(all(all)), all.end());
ll mn = (1ll<<50);
int mid = all[sz(all)/2];
for (int i = max(0, mid-100); i <= min((int)1e9, 100+mid); ++i) {
ll res = 0;
for (auto [l, r] : v) {
if (i < l) {
res += (l-i)*2ll;
}
if (i > r) {
res += (i-r)*2ll;
}
}
mn = min(mn, res);
}
cout << ans + mn, exit(0);
}
void ma1n() {
int k, n;
cin >> k >> n;
ll ans = 0;
vector<pii> v;
vector<int> all;
for (int i = 0; i < n; ++i) {
char c1, c2;
int l, r;
cin >> c1 >> l >> c2 >> r;
if (l > r) swap(l, r);
ans += r-l;
if (c1 != c2) {
ans++;
v.pb({l, r});
all.pb(l);
all.pb(r);
}
}
if (all.empty()) {
cout << ans, exit(0);
}
if (k == 1) one(all, v, ans);
int x = all[sz(all)/3];
int y = all[sz(all)*2/3];
ll mIn = (1ll<<50);
for (int i = max(0, x-100); i <= min((int)1e9, x+100); ++i) {
for (int j = max(0, y-100); j <= min((int)1e9, y+100); ++j) {
ll res = 0;
for (auto [l, r] : v) {
if (l <= i && i <= r) continue;
if (l <= j && j <= r) continue;
ll mn = INF;
if (i < l) mn = min(mn, (l-i)*2ll);
if (j < l) mn = min(mn, (l-j)*2ll);
if (mn != INF) res += mn;
mn = INF;
if (i > r) mn = min(mn, (i-r)*2ll);
if (j > r) mn = min(mn, (j-r)*2ll);
if (mn != INF) res += mn;
}
mIn = min(mIn, res);
}
}
cout << ans+mIn;
}
int main() {
ios_base::sync_with_stdio(0);
cin.tie(nullptr), fin();
int ts = 1;
if (flag) {
cin >> ts;
}
while (ts--) {
ma1n();
}
return 0;
}
