#include<bits/stdc++.h>
using namespace std;
using i64 = long long;
#define int i64
#define vi vector<int>
#define vvi vector<vi>
#define vb vector<bool>
#define pii pair<int, int>
#define fi first
#define se second
#define sz(x) (int)(x).size()
vector<pii> opp;
multiset<int> up, low;
int sup = 0, slow = 0;
inline void ins(int val, int len){
if(low.empty()){
low.insert(val);
slow += val;
}
else if(val > *low.rbegin()){
up.insert(val);
sup += val;
if(sz(up) > len / 2){
sup -= *up.begin();
slow += *up.begin();
low.insert(*up.begin());
up.erase(up.begin());
}
}
else{
low.insert(val);
slow += val;
if(sz(low) > (len + 1) / 2){
sup += *low.rbegin();
slow -= *low.rbegin();
up.insert(*low.rbegin());
low.erase(low.find(*low.rbegin()));
}
}
}
inline void er(int val){
auto pos = up.find(val);
if(pos != up.end()){
sup -= val;
up.erase(pos);
}
else{
slow -= val;
low.erase(low.find(val));
}
if(low.empty()){
slow += *up.begin();
sup -= *up.begin();
low.insert(*up.begin());
up.erase(up.begin());
}
}
inline int cost(){
return (*low.rbegin() * sz(low) - slow) + (sup - *low.rbegin() * sz(up));
}
signed main(){
ios_base::sync_with_stdio(false); cin.tie(0);
int k, n, h, o, ans, plus = 0;
char home, office;
cin >> k >> n;
vector<pii> opp;
for(int i = 0; i < n; i++){
cin >> home >> h >> office >> o;
if(home == office){
plus += abs(o - h);
}
else{
opp.emplace_back(h, o);
plus++;
}
}
n = sz(opp);
vi pref_ans(n);
sort(opp.begin(), opp.end(), [&](const pii &a, const pii &b) {return a.fi + a.se > b.fi + b.se;} );
for(int i = 0; i < n; i++){
ins(opp[i].fi, i * 2 + 1);
ins(opp[i].se, i * 2 + 2);
pref_ans[i] = cost();
}
if(k == 1)
ans = pref_ans.back();
else{
ans = pref_ans.back();
for(int i = 0; i < n - 1; i++){
er(opp[i].fi);
er(opp[i].se);
ans = min(ans, pref_ans[i] + cost());
}
}
cout << ans + plus;
return 0;
}
