// Born_To_Laugh - Hughie Do
#include <bits/stdc++.h>
#define alle(AC) AC.begin(), AC.end()
#define fi first
#define se second
using namespace std;
typedef long long ll;
[[maybe_unused]] const int MOD = 998244353, INF = 1e9 + 7;
const int maxn = 1e5 + 10;
int m, k, n;
pair<int, int> item[maxn];
ll pref[maxn], suff[maxn];
priority_queue<int> pql; // max heap
priority_queue<int, vector<int>, greater<>> pqr; // min heap
ll suml = 0, sumr = 0; // sumr - x * k + x * k - suml
void balance(){
if(pql.size() == pqr.size()) return;
if(pql.size() > pqr.size()){
int x = pql.top();
pql.pop();
pqr.push(x);
suml -= x;
sumr += x;
}
if(pqr.size() > pql.size()){
int x = pqr.top();
pqr.pop();
pql.push(x);
sumr -= x;
suml += x;
}
}
void solve(){
cin >> k >> m;
ll basecost = 0; n = 0;
for(int i=1; i<=m; ++i){
char p, q; int s, t;
cin >> p >> s >> q >> t;
if(s > t) swap(s, t);
if(p == q) basecost += t - s;
else{
item[++n] = {s, t};
basecost++;
}
}
sort(item + 1, item + 1 + n, [](pair<int, int> a, pair<int, int> b){
return a.fi + a.se < b.fi + b.se;
});
for(int i=1; i<=n; ++i){
if(pql.empty() || item[i].fi <= pql.top()){
pql.push(item[i].fi);
suml += item[i].fi;
}
else{
pqr.push(item[i].fi);
sumr += item[i].fi;
}
if(pql.empty() || item[i].se <= pql.top()){
pql.push(item[i].se);
suml += item[i].se;
}
else{
pqr.push(item[i].se);
sumr += item[i].se;
}
balance();
pref[i] = sumr - suml;
}
pql = priority_queue<int>();
pqr = priority_queue<int, vector<int>, greater<>>();
suml = sumr = 0;
for(int i=n; i>=1; --i){
if(pql.empty() || item[i].fi <= pql.top()){
pql.push(item[i].fi);
suml += item[i].fi;
}
else{
pqr.push(item[i].fi);
sumr += item[i].fi;
}
if(pql.empty() || item[i].se <= pql.top()){
pql.push(item[i].se);
suml += item[i].se;
}
else{
pqr.push(item[i].se);
sumr += item[i].se;
}
balance();
suff[i] = sumr - suml;
}
ll ans = basecost + pref[n];
if(k == 2){
for(int i=0; i<=n; ++i) ans = min(ans, basecost + pref[i] + suff[i + 1]);
}
cout << ans << '\n';
}
signed main(){
// freopen("inp.txt", "r", stdin);
// freopen("out.txt", "w", stdout);
ios_base::sync_with_stdio(false);
cin.tie(nullptr);
solve();
}
