#include <bits/stdc++.h>
#define IOS ios_base::sync_with_stdio(false);cin.tie();cout.tie();
#define all(x, y) x.begin(), x.begin() + y
#define int long long
#define pq priority_queue
#define eb emplace_back
#define lb lower_bound
#define ub upper_bound
#define pb push_back
#define pp pop_back
#define F first
#define S second
using namespace std;
struct pii {
int l, r;
bool operator<(pii b) const { return l + r < b.l + b.r; }
};
void solve () {
int k, n, m = 0;
cin >> k >> n;
vector<pii> v(n);
vector<int> a(n);
int s = 0, w = 0;
for (int l, r, i = 0; i < n; i++) {
char c, h;
cin >> c >> l >> h >> r;
if (l > r) swap(l, r);
if (c != h) v[m++] = {l, r};
else s += r - l;
}
s += n = m;
sort(all(v, n));
pq<int> L, R;
auto add = [&](pii p) {
L.push(p.l);
R.push(-p.r);
w += p.r - p.l;
if (L.top() > -R.top()) {
int l = L.top();
int r = -R.top();
L.pop();
R.pop();
L.push(r);
R.push(-l);
w += (l - r) * 2;
}
return w;
};
for (int i = 0; i < n; i++) a[i] = add(v[i]);
w = 0;
pq<int> ().swap(L);
pq<int> ().swap(R);
int t = n ? a[n-1] : 0;
if (n && k == 2) for (int i = n; --i;) t = min(t, add(v[i]) + a[i-1]);
cout << s + t;
}
signed main() {IOS solve(); return 0;}
