/* made by amunduzbaev */
#include <bits/stdc++.h>
//#include <ext/pb_ds/assoc_container.hpp>
//#include <ext/pb_ds/tree_policy.hpp>
using namespace std;
//using namespace __gnu_pbds;
#define ff first
#define vv vector
#define ss second
#define pb push_back
#define mp make_pair
#define ub upper_bound
#define lb lower_bound
#define sz(x) (int)x.size()
#define tut(x) array<int, x>
#define all(x) x.begin(), x.end()
#define rall(x) x.rbegin(),x.rend()
#define NeedForSpeed ios::sync_with_stdio(0);cin.tie(0);cout.tie(0);
#define int long long
typedef long long ll;
typedef long double ld;
typedef pair<int, int> pii;
typedef vector<int> vii;
typedef vector<pii> vpii;
template<class T> bool umin(T& a, const T& b) { return a > b? a = b, true:false; }
template<class T> bool umax(T& a, const T& b) { return a < b? a = b, true:false; }
//void usaco(string s) { freopen((s+".in").c_str(),"r",stdin);
//freopen((s+".out").c_str(),"w",stdout); }
//template<class T> tree<T,
//less<T>, null_type, rb_tree_tag,
//tree_order_statistics_node_update> ordered_set;
const int N = 2e5+5;
const int mod = 1e9+7;
const ll inf = 1e18;
const ld Pi = acos(-1);
#define MULTI 0
int n, m, k, ans, q, res, a[N];
int pref[N], suf[N];
/*
1 5
B 0 A 4
B 1 B 3
A 5 B 7
B 2 A 6
B 1 A 7
2 5
B 0 A 4
B 1 B 3
A 5 B 7
B 2 A 6
B 1 A 7
*/
void solve(int t_case){
cin>>k>>n;
vpii tt;
vii pp;
for(int i=0;i<n;i++){
char a, b; int l, r; cin>>a>>l>>b>>r;
if(a == b) res += abs(r - l);
else tt.pb({min(l, r), max(l, r)});
}
ans = 0;
vpii tt2;
for(int i=0;i<sz(tt);i++) tt2.pb({tt[i].ff + tt[i].ss, i});
sort(all(tt2));
multiset<int> lx, rx;
int rs = 0, ls = 0;
for(int i=0;i<sz(tt2);i++){
int in = tt2[i].ss;
rx.insert(tt[in].ff), rx.insert(tt[in].ss);
rs += tt[in].ff + tt[in].ss;
lx.insert(*rx.begin()), ls += *rx.begin(), rs -= *rx.begin(), rx.erase(rx.begin());
pref[i] = rs - ls;
} lx.clear(), rx.clear(), ls = rs = 0;
for(int i=sz(tt2)-1;i>=0;i--){
int in = tt2[i].ss;
lx.insert(tt[in].ff), lx.insert(tt[in].ss);
ls += tt[in].ff + tt[in].ss;
rx.insert(*--lx.end()), rs += *--lx.end(), ls -= *--lx.end(), lx.erase(--lx.end());
suf[i] = rs - ls;
} ans = suf[0];
if(k == 2)
for(int i=0;i+1<sz(tt2);i++) umin(ans, pref[i] + suf[i+1]);
//cout<<ans<<" "<<res<<e" "<<sz(tt)<<"\n";
cout<<ans + res + sz(tt)<<"\n";
}
signed main(){
NeedForSpeed
if(!MULTI) {
solve(1);
} else {
int t; cin>>t;
for(int t_case = 1; t_case <= t; t_case++) solve(t_case);
} return 0;
}
