#include <bits/stdc++.h>
#define FOR(i, x, y) for (int i = x; i < y; i++)
typedef long long ll;
using namespace std;
bool cmp(pair<int, int> a, pair<int, int> b) {
return a.first + a.second < b.first + b.second;
}
priority_queue<int> lpq;
priority_queue<int, vector<int>, greater<int>> rpq;
ll lsum, rsum;
void insert(int x) {
int median = (lpq.size() ? lpq.top() : 1000000001);
if (x <= median) {
lpq.push(x);
lsum += x;
} else {
rpq.push(x);
rsum += x;
}
if (rpq.size() + 1 < lpq.size()) {
int nxt = lpq.top();
lpq.pop();
rpq.push(nxt);
lsum -= nxt;
rsum += nxt;
} else if (lpq.size() < rpq.size()) {
int nxt = rpq.top();
rpq.pop();
lpq.push(nxt);
rsum -= nxt;
lsum += nxt;
}
}
ll pref[100001];
int main() {
ios_base::sync_with_stdio(0);
cin.tie(0);
int k, n;
ll ss = 0;
vector<pair<int, int>> v = {{0, 0}};
cin >> k >> n;
FOR(i, 0, n) {
char a, b;
int x, y;
cin >> a >> x >> b >> y;
if (a == b) ss += abs(x - y);
else v.push_back({x, y});
}
sort(v.begin(), v.end(), cmp);
n = v.size() - 1;
ss += n;
lsum = rsum = 0;
FOR(i, 1, n + 1) {
insert(v[i].first);
insert(v[i].second);
pref[i] = rsum - lsum;
}
ll ans = pref[n];
if (k == 2) {
while (lpq.size()) lpq.pop();
while (rpq.size()) rpq.pop();
lsum = rsum = 0;
for (int i = n; i; i--) {
insert(v[i].first);
insert(v[i].second);
ans = min(ans, rsum - lsum + pref[i - 1]);
}
}
cout << ss + ans;
return 0;
}
