#include <bits/stdc++.h>
using namespace std;
typedef long long ll;
typedef vector <int> vi;
typedef pair <ll,ll> pi;
#define pb push_back
#define f first
#define s second
#define OO 1e9
#define all(x) (x).begin(), (x).end()
bool cmp(const pi &a,const pi &b){
return a.f + a.s < b.f + b.s;
}
priority_queue <int> pl;
priority_queue <int, vi, greater<int>> pr;
ll pref[100001], lsum, rsum;
void in(int x){
int median = pl.size() ? pl.top() : 1000000001;
if(x <= median){
pl.push(x);
lsum += x;
}else{
pr.push(x); rsum += x;
}
if(pl.size() > pr.size() + 1){
int nxt = pl.top();
pl.pop(); lsum -= nxt;
pr.push(nxt); rsum += nxt;
}else if(pr.size() > pl.size()){
int nxt = pr.top();
pr.pop(); rsum -= nxt;
pl.push(nxt); lsum += nxt;
}
}
int main() {
// ios::sync_with_stdio(0); cin.tie(0);
// freopen("art2.in", "r", stdin);
// freopen("art2.out", "w", stdout);
int k,n; cin>>k>>n;
vector <pi> v{{0, 0}};
ll same_side = 0;
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.pb({x, y});
}
sort(all(v), cmp);
n = v.size()-1;
same_side += n;
for(int i=1; i<=n; ++i){
in(v[i].f);
in(v[i].s);
pref[i] = rsum-lsum;
}
ll ans = pref[n];
if(k == 2){
while(pl.size()) pl.pop();
while(pr.size()) pr.pop();
rsum = 0; lsum = 0;
for(int i=n; i>=1; --i){
in(v[i].f);
in(v[i].s);
ans = min(ans, pref[i-1] + rsum-lsum);
}
}
cout << ans+same_side;
return 0;
}
