// #pragma GCC optimize("O3,unroll-loops")
// #pragma GCC target("avx2,bmi,bmi2,lzcnt,popcnt")
#include <bits/stdc++.h>
#include <ext/pb_ds/assoc_container.hpp>
using namespace std;
using namespace __gnu_pbds;
template <class T>
using ordered_set = tree<T, null_type, less<T>, rb_tree_tag, tree_order_statistics_node_update>;
#define endl '\n';
#define fastio ios_base::sync_with_stdio(false); cin.tie(0); cout.tie(0);
#define py cout << "YES" << endl;
#define pn cout << "NO" << endl;
#define pb push_back
#define int long long
typedef long long ll;
typedef unsigned long long ull;
const ll inf = 1e18;
const ll mod = 1e9+7;
#ifndef ONLINE_JUDGE
#include "algo/Standard_Stuff/debug.cpp"
#else
#define debug(...) 42
#endif
void judge(){
srand(time(NULL));
#ifndef ONLINE_JUDGE
freopen("1.txt","r",stdin);
freopen("2.txt","w",stdout);
#endif
}
struct min_priority_queue{
priority_queue<int>pq;
void push(int x){
pq.push(-1*x);
}
int top(){
// assert(pq.size()!=0);
return -1*pq.top();
}
void pop(){
pq.pop();
}
int size(){
return pq.size();
}
};
struct SlidingMedian{
priority_queue<int>pq1;
min_priority_queue pq2;
int sum1 = 0, sum2 = 0;
void insert(int x){
if(pq1.size()==0){
sum1 += x;
pq1.push(x); return;
}
if(pq2.size()==(int)pq1.size()-1){
int y = pq1.top();
if(y<=x){
sum2 += x;
pq2.push(x);
}
else{
sum1 -= y;
pq1.pop();
pq1.push(x);
sum1 += x;
sum2 += y;
pq2.push(y);
}
return;
}
int x2 = pq2.top();
if(x<=x2){
sum1 += x;
pq1.push(x); return;
}
// assert(pq2.size()!=0);
pq2.pop();
sum2 -= x2;
sum2 += x;
sum1 += x2;
pq2.push(x);
pq1.push(x2);
}
int median(){
//assert(pq1.size()!=0);
return pq1.top();
}
int diff(){
int m = median();
int s1 = m*pq1.size()-sum1;
int s2 = sum2 - m*pq2.size();
return s1 + s2;
}
void empty(){
while(pq1.size()){
pq1.pop();
}
while(pq2.size()){
pq2.pop();
}
sum1 = sum2 = 0;
}
};
signed main(){
fastio;
int k,n; cin >> k >> n;
int ans = 0;
vector<pair<int,pair<int,int>>>a;
for(int i = 0;i<n;i++){
char p,q; int x,y; cin >> p >> x >> q >> y;
if(p==q){
ans += abs(x-y); continue;
}
a.pb({x+y,{min(x,y),max(x,y)}});
}
n = a.size();
if(n==0){
cout << ans; return 0;
}
// assert(n!=0);
sort(a.begin(),a.end());
ans += n;
vector<int>left(n),right(n);
SlidingMedian window;
for(int i = 0;i<n;i++){
window.insert(a[i].second.first);
window.insert(a[i].second.second);
left[i] = window.diff();
}
window.empty();
for(int i = n-1;i>=0;i--){
window.insert(a[i].second.first);
window.insert(a[i].second.second);
right[i] = window.diff();
}
if(k==1){
cout << ans + left[n-1]; return 0;
}
int best = left[n-1];
for(int i = 0;i<n-1;i++){
best = min(best,left[i]+right[i+1]);
}
cout << ans + best;
}
