#include <cstdio>
#include <iostream>
#include <algorithm>
#include <string>
#include <cstring>
#include <vector>
#include <queue>
#include <set>
#include <map>
#include <cmath>
#include <iomanip>
#include <cassert>
#include <bitset>
using namespace std;
typedef pair<int, int> P;
#define rep(i, n) for (int i=0; i<(n); i++)
#define all(c) (c).begin(), (c).end()
#define uniq(c) c.erase(unique(all(c)), (c).end())
#define index(xs, x) (int)(lower_bound(all(xs), x) - xs.begin())
#define _1 first
#define _2 second
#define pb push_back
#define INF 1145141919
#define MOD 1000000007
struct BIT {
int n;
vector<long long> xs;
BIT (int n) : n(n) { xs.resize(n+1); }
void add(int i, int v) {
for (int x=i+1; x<=n; x+=x&-x) xs[x] += v;
}
long long sum(int i) {
long long s = 0;
for (int x=i+1; x>0; x-=x&-x) s += xs[x];
return s;
}
};
int K, N;
vector<int> xs;
vector<long long> solve(vector<P> ps) {
vector<long long> ret;
ret.pb(0);
BIT sum(xs.size()), num(xs.size());
long long cs = 0, total_sum = 0, total_num = 0;
auto f = [&](long long X) {
int p = (int)(upper_bound(all(xs), X) - xs.begin())-1;
long long s = sum.sum(p), n = num.sum(p);
return ((total_sum-s) - 1LL*X*(total_num-n)) + (1LL*X*n-s) + cs;
};
for (P p : ps) {
int l = p._1-p._2, r = p._2;
int lp = index(xs, l), rp = index(xs, r);
// [l, r]
// f(x) += |x-l| + |x-r| - (r-l)
sum.add(lp, l), num.add(lp, 1);
sum.add(rp, r), num.add(rp, 1);
total_sum += l+r;
total_num += 2;
cs -= r-l;
int lo = 0, hi = 1e9+5;
while (hi - lo > 1) {
int mid = (lo + hi) / 2;
if (f(mid) - f(mid-1) <= 0) lo = mid;
else hi = mid;
}
ret.pb(f(lo));
}
return ret;
}
signed main() {
ios::sync_with_stdio(false); cin.tie(0);
cin >> K >> N;
long long sum = 0;
vector<P> ps;
rep(i, N) {
char a, b;
int x, y;
cin >> a >> x >> b >> y;
if (x > y) swap(x, y);
sum += y-x;
if (a != b) {
sum++,
ps.pb(P(x+y, y));
}
xs.pb(x), xs.pb(y);
}
sort(all(xs)); uniq(xs);
int n = ps.size();
sort(all(ps));
vector<long long> l = solve(ps);
if (K == 1) {
cout << sum + l[n] << "\n";
return 0;
}
reverse(all(ps));
vector<long long> r = solve(ps);
long long m = 1LL<<60;
rep(i, n+1) m = min(m, sum + l[i] + r[n-i]);
cout << m << "\n";
return 0;
}
