/// 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 ma1n() {
int k, n;
cin >> k >> n;
if (k == 2) return;
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);
}
}
n = sz(v);
if (all.empty()) {
cout << ans, exit(0);
}
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-1000); i <= min((int)1e9, 1000+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;
}
int main() {
ios_base::sync_with_stdio(0);
cin.tie(nullptr), fin();
int ts = 1;
if (flag) {
cin >> ts;
}
while (ts--) {
ma1n();
}
return 0;
}
