#include <bits/stdc++.h>
using namespace std;
#define int long long
#define endl "\n"
#define pb push_back
#define ff first
#define ss second
#define ii pair<int, int>
#define vi vector<int>
#define vii vector<pair<int, int>>
#define yes cout << "YES\n"
#define no cout << "NO\n"
#define mii map<int, int>
#define rep(i, a, b) for (int i = a; i <= b; i++)
#define all(a, len) (a) + 1, (a) + len + 1
#define vall(a) (a).begin(), a.end()
#define _READ(name) freopen(name, "r", stdin)
#define _WRITE(name) freopen(name, "w", stdout)
const int INF = 4e18;
const int MOD = 1e9 + 7;
int k, n;
multiset<int> ms1, ms2;
int suml, sumr;
void insert(int x) {
if (ms2.size() && *ms2.begin() < x) {
ms2.insert(x);
sumr += x;
} else {
ms1.insert(x);
suml += x;
}
if (ms1.size() > ms2.size() + 1) {
int last = *ms1.rbegin();
ms2.insert(last);
ms1.erase(ms1.find(last));
suml -= last; sumr += last;
}
if (ms2.size() > ms1.size()) {
int first = *ms2.begin();
ms1.insert(first);
ms2.erase(ms2.find(first));
sumr -= first; suml += first;
}
}
int pref[100005];
signed main() {
ios_base::sync_with_stdio(false);
cin.tie(nullptr); cout.tie(nullptr);
cin >> k >> n;
vii a;
int same = 0;
while (n--) {
char p, q; int s, t; cin >> p >> s >> q >> t;
if (p == q) {
same += abs(s-t);
} else {
a.pb({s, t});
}
}
n = a.size()-1;
same += n + 1;
sort(a.begin(), a.end(), [](ii x, ii y) {
return x.ff + x.ss < y.ff + y.ss;
});
for (int i = 0; i <= n; i++) {
insert(a[i].ff); insert(a[i].ss);
pref[i] = sumr - suml;
}
if (k == 1) {
cout << pref[n] + same; return 0;
}
ms1.clear(); ms2.clear();
int ans = pref[n];
suml = sumr = 0;
for (int i = n; i > 0; i--) {
insert(a[i].ff); insert(a[i].ss);
ans = min(ans, sumr - suml + pref[i-1]);
}
cout << ans + same;
return 0;
}
