#include <iostream>
#include<string>
#include<cmath>
#include<map>
#include<iomanip>
#include<algorithm>
#include<vector>
#include<set>
#include<cstdio>
#include<stack>
#include<ctime>
#include<queue>
#include<deque>
#include<bitset>
#include<random>
#include<fstream>
#include<unordered_map>
#include<unordered_set>
using namespace std;
using ll = long long;
using ld = long double;
using ull = unsigned long long;
using uint = unsigned int;
using dbl = double;
# define all(x) x.begin(), x.end()
# define rall(x) x.rbegin(), x.rend()
#pragma GCC optimize("O3,unroll-loops")
#pragma GCC target("avx2,bmi,bmi2,lzcnt,popcnt")
ll gcd(ll a, ll b) {
return b == 0 ? a : gcd(b, a % b);
}
ll lcm(ll a, ll b) {
return a / gcd(a, b) * b;
}
ll bpow(ll a, ll n) {
return n == 0 ? 1 : n % 2 ? bpow(a, n - 1) * a : bpow(a * a, n / 2);
}
ll bpowm(ll a, ll n, ll m) {
return n == 0 ? 1 : n % 2 ? bpowm(a, n - 1, m) * a % m : bpowm(a * a % m, n / 2, m);
}
mt19937 mt(time(0));
const int N = 1e5 + 2, inf = 1e9 + 100, mod = 1e9 + 7, mod2 = 998244353, P = 257;
const ll llinf = 1e18 + 1000;
struct st {
int a, b;
};
bool cmp(st a, st b) {
return a.a + a.b < b.a + b.b;
}
vector<int> sz;
struct segtree {
struct node {
ll sum;
int cnt;
node() : sum(0), cnt(0) {}
};
node t[N * 4];
segtree() {
fill(t, t + N * 4, node());
}
void upd(int v, int l, int r, int i, int val) {
t[v].sum += sz[i] * val;
t[v].cnt += val;
if (r - l == 1) return;
int m = (l + r) >> 1;
if (i < m) upd(v + 1, l, m, i, val);
else
upd(v + 2 * (m - l), m, r, i, val);
}
void upd(int i, int val) {
upd(0, 0, sz.size(), i, val);
}
ll get(int v, int l, int r, int k) {
if (r - l == 1) {
return 1ll * sz[l] * (t[v].cnt - k) - 1ll * sz[l] * k;
}
int m = (l + r) >> 1;
if (t[v + 1].cnt <= k) return get(v + 2 * (m - l), m, r, k - t[v + 1].cnt) - t[v + 1].sum;
else
return get(v + 1, l, m, k) + t[v + 2 * (m - l)].sum;
}
ll get() {
return get(0, 0, sz.size(), t[0].cnt / 2);
}
};
segtree t1, t2;
void solve() {
int n, k;
cin >> k >> n;
vector<st> a;
ll add = 0;
for (int i = 0; i < n; ++i) {
char c1, c2;
int x1, x2;
cin >> c1 >> x1 >> c2 >> x2;
if (c1 != c2) {
a.push_back({ x1, x2 });
sz.push_back(x1);
sz.push_back(x2);
}
else {
add += abs(x1 - x2);
}
}
n = a.size();
sort(all(a), cmp);
sort(all(sz));
sz.erase(unique(all(sz)), sz.end());
for (int i = 0; i < n; ++i) {
a[i].a = lower_bound(all(sz), a[i].a) - sz.begin();
a[i].b = lower_bound(all(sz), a[i].b) - sz.begin();
}
ll ans = llinf;
for (int i = 0; i < n; ++i) {
t2.upd(a[i].a, 1);
t2.upd(a[i].b, 1);
}
ans = t2.get();
if (k == 1) {
cout << ans + add + n;
return;
}
for (int i = 0; i < n; ++i) {
t1.upd(a[i].a, 1);
t1.upd(a[i].b, 1);
t2.upd(a[i].a, -1);
t2.upd(a[i].b, -1);
ans = min(ans, t1.get() + t2.get());
}
cout << ans + add + n;
}
signed main() {
ios::sync_with_stdio(0);
cin.tie(0);
cout.tie(0);
//freopen("coloring.in", "r", stdin);
//freopen("coloring.out", "w", stdout);
//ld time1 = clock();
int tt = 1;
//cin >> tt;
while (tt--) {
solve();
cout << '\n';
cout.flush();
}
//ld time2 = clock();
//cerr << "\n\nTIME: " << (time2 - time1) / CLOCKS_PER_SEC;
return 0;
}
