#include <bits/stdc++.h>
using namespace std;
using ll = long long;
multiset<ll> ini_1, fim_1, ini_2, fim_2;
ll sum_ini_1, sum_fim_1, sum_ini_2, sum_fim_2;
void add_begin(int a){
if(!ini_1.empty() && a > *ini_1.rbegin()){
sum_fim_1 += a;
fim_1.insert(a);
} else{
sum_ini_1 += a;
ini_1.insert(a);
}
while(fim_1.size() < ini_1.size()){
fim_1.insert(*ini_1.rbegin());
sum_fim_1 += *ini_1.rbegin();
sum_ini_1 -= *ini_1.rbegin();
ini_1.erase(ini_1.find(*ini_1.rbegin()));
}
while(ini_1.size() < fim_1.size()){
ini_1.insert(*fim_1.begin());
sum_ini_1 += *fim_1.begin();
sum_fim_1 -= *fim_1.begin();
fim_1.erase(fim_1.begin());
}
}
void remove_end(int a){
if(ini_2.find(a) != ini_2.end()){
sum_ini_2 -= a;
ini_2.erase(ini_2.find(a));
} else{
sum_fim_2 -= a;
fim_2.erase(fim_2.find(a));
}
while(fim_2.size() < ini_2.size()){
fim_2.insert(*ini_2.rbegin());
sum_fim_2 += *ini_2.rbegin();
sum_ini_2 -= *ini_2.rbegin();
ini_2.erase(ini_2.find(*ini_2.rbegin()));
}
while(ini_2.size() < fim_2.size()){
ini_2.insert(*fim_2.begin());
sum_ini_2 += *fim_2.begin();
sum_fim_2 -= *fim_2.begin();
fim_2.erase(fim_2.begin());
}
}
ll solve(){
ll left = 0, right = 0;
if(!ini_1.empty()){
int m_1 = *ini_1.rbegin();
left = m_1 * ((int) ini_1.size()) - sum_ini_1 + sum_fim_1 - m_1 * ((int) fim_1.size());
}
if(!ini_2.empty()){
int m_2 = *ini_2.rbegin();
right = m_2 * ((int) ini_2.size()) - sum_ini_2 + sum_fim_2 - m_2 * ((int) fim_2.size());
}
return left + right;
}
int main(){
cin.tie(0)->sync_with_stdio(0);
int k, n; cin >> k >> n;
ll x = 0;
vector<int> a;
vector<pair<int, int>> v;
for(int i=1; i<=n; i++){
char p, q; int s, t; cin >> p >> s >> q >> t;
if(p == q){
x += abs(s - t);
} else{
x ++;
a.push_back(s), a.push_back(t);
v.push_back({s + t, s});
}
}
sort(a.begin(), a.end());
sort(v.begin(), v.end());
ll ans = 0;
for(int i=0; i<a.size(); i++) ans += abs(a[i] - a[a.size() / 2]);
if(k == 1){
cout << ans + x << "\n";
return 0;
}
for(int i=0; i<v.size(); i++){
fim_2.insert(v[i].first - v[i].second);
fim_2.insert(v[i].second);
sum_fim_2 += v[i].first;
}
while(ini_2.size() < fim_2.size()){
ini_2.insert(*fim_2.begin());
sum_ini_2 += *fim_2.begin();
sum_fim_2 -= *fim_2.begin();
fim_2.erase(fim_2.begin());
}
for(int i=0; i<v.size(); i++){
add_begin(v[i].first - v[i].second), add_begin(v[i].second);
remove_end(v[i].first - v[i].second), remove_end(v[i].second);
ans = min(ans, solve());
}
cout << ans + x << "\n";
return 0;
}
