#include <bits/stdc++.h>
using namespace std;
#define ll long long
#define pb push_back
#define pii pair<int,int>
#define f first
#define s second
#define chmin(a, b) a = min(a,b)
#define chmax(a, b) a = max(a,b)
#define FOR(i, a, b) for (int i = (a); i < (b); i++)
#define F0R(i, a) for (int i = 0; i < (a); i++)
#define all(x) x.begin(),x.end()
#define v vector
int main() {
ios::sync_with_stdio(false); cin.tie(0);
int n, k; cin >> k >> n;
ll add = 0;
v<pii> people;
F0R(i,n) {
char a, b; int c, d;
cin >> a >> c >> b >> d;
if (a==b) {add += abs(d-c);}
else {
people.pb({c,d});
}
}
sort(all(people),[&](pii a, pii b) {return a.f+a.s<b.f+b.s;});
//ll ans1 = 0;
//for (int i : pos) {ans1 += abs(i-pos[(pos.size()-1)/2]);}
v<ll> cost(people.size()+1,0), cost2(people.size()+1,0);
F0R(cnt,2) {
multiset<ll> left, right;
ll lsum = 0, rsum = 0;
int c = 0;
auto doit = [&](int a) {
c++;
if (right.size() && a>*right.begin()) {right.insert(a); rsum += a;}
else {left.insert(a); lsum += a;}
if (left.size()>(c+1)/2) {
int d = *left.rbegin();
lsum -= d; rsum += d;
right.insert(d);
left.erase(left.find(d));
} else if (right.size()>c-(c+1)/2) {
int d = *right.begin();
lsum += d; rsum -= d;
right.erase(right.find(d));
left.insert(d);
}
};
F0R(i,people.size()) { // split past i
doit(people[i].f); doit(people[i].s);
ll med = *left.rbegin();
cost[i+1] = (med*left.size()-lsum) + (rsum-med*right.size());
//cout << cost[i+1] << '\n';
}
swap(cost,cost2);
reverse(all(people));
//break;
}
ll ans = cost.back();
if (k==2) {
F0R(i,people.size()) {
chmin(ans,cost[i]+cost2[people.size()-i]);
}
}
cout << ans+add+people.size() << '\n';
/*
get rid of p=q first
make sure start<end
one bridge
do median
two bridges
sort people by bottom then top
fix breakpoint for people and calc medians of each
multiset for smaller elements and multiset for larger elements
adding new element:
add to correct multiset and shift elements between them
store sum for both multisets
*/
}
