#include<bits/stdc++.h>
#define X first
#define Y second
#define all(x) begin(x), end(x)
#define FOR(i, a, b) for(int i = (a); i <= (b); i++)
#define FORD(i, b, a) for(int i = (b); i >= (a); i--)
#define REP(i, a, b) for (int i = (a); i < (b); i++)
#define mxx max_element
#define mnn min_element
#define SQR(x) (1LL * (x) * (x))
#define MASK(i) (1LL << (i))
#define Point Vector
#define left Left
#define right Right
#define div Div
using namespace std;
typedef long long ll;
typedef unsigned long long ull;
typedef double db;
typedef long double ld;
typedef pair<db, db> pdb;
typedef pair<ld, ld> pld;
typedef pair<int, int> pii;
typedef pair<int, pii> piii;
typedef pair<ll, ll> pll;
typedef pair<ll, pll> plll;
typedef pair<ll, int> pli;
typedef pair<ll, pii> plii;
template<class A, class B>
bool maximize(A& x, B y) {
if (x < y) return x = y, true; else return false;
}
template<class A, class B>
bool minimize(A& x, B y) {
if (x > y) return x = y, true; else return false;
}
/* END OF TEMPLATE */
const int N = 3e5 + 7;
int n, k;
vector<pii> seg;
ll res = 0;
priority_queue<int, vector<int>> left;
priority_queue<int, vector<int>, greater<int>> right;
ll lsum = 0, rsum = 0;
ll pre[N], suf[N];
void insert_value(int x) {
int median = (left.empty() ? 1000000007 : left.top());
if (x <= median) {
left.push(x);
lsum+=x;
}
else {
right.push(x);
rsum+=x;
}
if (left.size() == right.size()) return ;
if ((int)left.size() > (int)right.size() + 1) {
lsum-=left.top();
rsum+=left.top();
right.push(left.top());
left.pop();
}
else
if ((int)left.size() < (int)right.size()) {
rsum-=right.top();
lsum+=right.top();
left.push(right.top());
right.pop();
}
}
int main() {
ios_base::sync_with_stdio(0);
cin.tie(0);
cin>>k>>n;
FOR(i, 1, n) {
char P, Q;
int A, B;
cin>>P>>A>>Q>>B;
if (P == Q) res+=abs(A - B);
if (P != Q) seg.push_back({min(A, B), max(A, B)}), res++;
}
if (seg.empty()) return cout<<res, 0;
seg.push_back({-1, -1});
sort(all(seg), [](pii a, pii b) {
return a.X + a.Y < b.X + b.Y;
});
pre[0] = 0;
n = (int)seg.size() - 1;
FOR(i, 1, n) {
insert_value(seg[i].X);
insert_value(seg[i].Y);
pre[i] = rsum - lsum;
}
if (k == 1) return cout<<pre[n] + res, 0;
while (!left.empty()) left.pop();
while (!right.empty()) right.pop();
lsum = 0;
rsum = 0;
ll ans = 1e18;
FORD(i, n, 1) {
insert_value(seg[i].X);
insert_value(seg[i].Y);
minimize(ans, rsum - lsum + res + pre[i - 1]);
}
cout<<ans;
return 0;
}
