#include <bits/stdc++.h>
using namespace std;
#define int long long
typedef pair<int,int> pi;
#define f first
#define s second
#define FAST ios_base::sync_with_stdio(0); cin.tie(0);
typedef pair<int, pi> pii;
#define all(x) x.begin(),x.end()
const int maxn = 100010;
const int INF = LLONG_MAX/2;
//If K=1, take median of all points X and Y independently
//Take b_left if x + y < b_right + b_left else take b_right
//Just have to find splitting point
//If unoptimal (take wrong bridge in wrong group) then whatever.
int pref[maxn];
int suf[maxn];
int k, n;
int bonus;
vector <pi> v;
pi pos[maxn];
priority_queue <int> q1;
priority_queue <int,vector<int>,greater<int>> q2;
int q1sum, q2sum;
void movee(int opt) {
if (opt and !q1.empty()) {
int x = q1.top();
q1.pop();
q2.push(x);
q1sum -= x;
q2sum += x;
} else if (!opt and !q2.empty()) {
int x = q2.top();
q2.pop();
q1.push(x);
q2sum -= x;
q1sum += x;
}
}
int findMed() {
if (q1.size() == 0 and q2.size() == 0) return 0;
if (q1.size() >= q2.size()) {
return q1.top();
} else {
return q2.top();
}
}
void check() {
if ((int)q1.size() > (int)q2.size() + 1) movee(1);
else if ((int)q2.size() > (int)q1.size() + 1) movee(0);
}
void insert(int x) {
int med = findMed();
if (x > med) {
q2.push(x);
q2sum += x;
} else {
q1.push(x);
q1sum += x;
}
check();
}
int32_t main() {
cin >> k >> n;
for (int i =0;i<n;i++) {
char a,b; cin >> a >> pos[i].f >> b >> pos[i].s;
if (a == b) bonus += abs(pos[i].f - pos[i].s);
else {
v.push_back(pi(pos[i].f+pos[i].s,i));
}
}
sort(all(v));
for (int i =0;i<(int)v.size();i++) {
int x = pos[v[i].s].f, y = pos[v[i].s].s;
insert(x);
insert(y);
int med = findMed();
pref[i] = (q2sum - med * q2.size()) + (med * q1.size() - q1sum);
}
if (k == 1) {
cout << pref[v.size()-1] + bonus + (int)v.size();
return 0;
}
while (!q1.empty()) q1.pop();
while (!q2.empty()) q2.pop();
q1sum = q2sum = 0;
for (int i =(int)v.size()-1;i>=0;i--) {
int x = pos[v[i].s].f, y = pos[v[i].s].s;
insert(x);
insert(y);
int med = findMed();
suf[i] = (q2sum - med * q2.size()) + (med * q1.size() - q1sum);
}
int ans = suf[0] + bonus + (int) v.size();
for (int i =0;i<(int)v.size();i++) {
ans = min(ans, pref[i] + suf[i+1] + bonus + (int)v.size());
}
cout << ans;
}
