#include <bits/stdc++.h>
using namespace std;
#define ll long long
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() {
int k,n;
ll same_side=0;
vector<pair<int,int>> v={{0,0}};
cin >> k >> n;
for (int i=0; i<n; i++) {
char a,b;
int x,y;
cin >> a >> x >> b >> y;
if (a==b) {
same_side+=abs(x - y);
} else {
v.push_back({x,y});
}
}
sort(v.begin(),v.end(),cmp);
n=v.size() - 1;
same_side+=n;
lsum=rsum=0;
for (int i=1; i<=n; i++) {
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 << same_side+ans;
return 0;
}
