#pragma GCC optimize("Ofast,O2,O3,unroll-loops")
#pragma GCC target("avx2")
#include <bits/stdc++.h>
using namespace std;
void debug_out() { cerr << endl; }
template<typename Head, typename... Tail>
void debug_out(Head H, Tail... T) {
cerr << "[" << H << "]";
debug_out(T...);
}
#ifdef dddxxz
#define debug(...) cerr << "[" << #__VA_ARGS__ << "]:", debug_out(__VA_ARGS__)
#else
#define debug(...) 42
#endif
#define SZ(s) ((int)s.size())
#define all(x) (x).begin(), (x).end()
#define lla(x) (x).rbegin(), (x).rend()
#define bpc(x) __builtin_popcount(x)
#define bpcll(x) __builtin_popcountll(x)
#define MP make_pair
clock_t startTime;
double getCurrentTime() {
return (double) (clock() - startTime) / CLOCKS_PER_SEC;
}
mt19937 rng(chrono::high_resolution_clock::now().time_since_epoch().count());
typedef long long ll;
const int MOD = 1e9 + 7;
const int INF = 1000000101;
const long long LLINF = 1223372000000000555;
const int N = 1e6 + 3e2;
const int M = 5555;
long long Solve_One_Bridge(const vector<int> &a, const vector<int> &b){
vector<int> c;
for (int i : a) c.push_back(i);
for (int i : b) c.push_back(i);
sort(all(c));
long long res = 0;
int mid = c[(int)c.size() / 2 - 1];
for (int i : c) res += abs(i - mid);
return res;
}
long long cost(const vector<int> &a, const vector<int> &b, int x, int y){
ll res = 0;
for (int i = 0; i < a.size(); i++){
res += min(abs(a[i] - x) + abs(b[i] - x), abs(a[i] - y) + abs(b[i] - y));
}
return res;
}
void solve(int TC) {
int k, n;
cin >> k >> n;
long long ans = 0;
vector<int> a, b;
while (n--){
char p, q;
int x, y;
cin >> p >> x >> q >> y;
if (p == q){
ans += abs(x - y);
} else {
ans++;
if (x > y) swap(x, y);
a.push_back(x);
b.push_back(y);
}
}
n = a.size();
if (n == 0){
cout << ans << endl;
return;
}
if (k == 1) {
cout << ans + Solve_One_Bridge(a, b) << endl;
return;
}
set<int> positions;
for (int i : a) positions.insert(i);
for (int i : b) positions.insert(i);
vector<int> pos;
for (int i : positions) pos.push_back(i);
ll best = LLINF;
for (int i = 0; i < pos.size(); i++){
int x = pos[i];
int l = i, r = pos.size() - 1;
while (r - l >= 3){
int m1 = l + (r - l) / 3;
int m2 = r - (r - l) / 3;
ll f1 = cost(a, b, x, pos[m1]);
ll f2 = cost(a, b, x, pos[m2]);
best = min({best, f1, f2});
if (f1 > f2){
l = m1;
} else {
r = m2;
}
}
for (int j = l; j <= r; j++) best = min(best, cost(a, b, x, pos[j]));
}
cout << ans + best << endl;
}
int main() {
startTime = clock();
ios_base::sync_with_stdio(false); cin.tie(nullptr); cout.tie(nullptr);
#ifdef dddxxz
freopen("input.txt", "r", stdin);
freopen("output.txt", "w", stdout);
#endif
int TC = 1;
// cin >> TC;
for (int test = 1; test <= TC; test++) {
//debug(test);
//cout << "Case #" << test << ": ";
solve(test);
}
#ifdef dddxxz
cerr << endl << "Time: " << int(getCurrentTime() * 1000) << " ms" << endl;
#endif
return 0;
}
