#ifndef _Alignof
#define _Alignof(x) __alignof__(x)
#endif
#include<bits/stdc++.h>
#include<ext/pb_ds/tree_policy.hpp>
#include<ext/pb_ds/assoc_container.hpp>
using namespace std;
using namespace __gnu_pbds;
#define vll vector<long long>
#define vpll vector< pair<long long int , long long int > >
#define rep(i,x,a) for (long long i=x; i<a; i++)
#define si(x) (long long int)x.size()
#define pb push_back
#define ff first
#define ss second
#define lg2(x) (long long int)log2(x)
#define gap " "
#define nl '\n'
#define all(x) (x).begin(),(x).end()
#define no cout<<"No\n"
#define yes cout<<"Yes\n"
#define vld vector<long double>
typedef long long ll;
typedef unsigned long long ull;
typedef long double lld;
#ifndef ONLINE_JUDGE
#define debug(x) cerr << #x <<" "; _print(x); cerr << endl;
#else
#define debug(x)
#endif
void _print(ll t) {cerr << t;}
void _print(int t) {cerr << t;}
void _print(string t) {cerr << t;}
void _print(char t) {cerr << t;}
void _print(lld t) {cerr << t;}
void _print(double t) {cerr << t;}
void _print(ull t) {cerr << t;}
void print(){
cout << '\n';
}
template<class T, class... Ts>
void print(const T& a, const Ts&... b){
cout << a;
(cout << ... << (cout << ' ', b));
cout << '\n';
}
template<class... T>
void input(T&... a){
(cin >> ... >> a);
}
template <class T, class V> void _print(pair <T, V> p);
template <class T> void _print(vector <T> v);
template <class T> void _print(set <T> v);
template <class T, class V> void _print(map <T, V> v);
template <class T> void _print(multiset <T> v);
template <class T, class V> void _print(pair <T, V> p) {cerr << "{"; _print(p.ff); cerr << ","; _print(p.ss); cerr << "}";}
template <class T> void _print(vector <T> v) {cerr << "[ "; for (T i : v) {_print(i); cerr << " ";} cerr << "]";}
template <class T> void _print(set <T> v) {cerr << "[ "; for (T i : v) {_print(i); cerr << " ";} cerr << "]";}
template <class T> void _print(multiset <T> v) {cerr << "[ "; for (T i : v) {_print(i); cerr << " ";} cerr << "]";}
template <class T, class V> void _print(map <T, V> v) {cerr << "[ "; for (auto i : v) {_print(i); cerr << " ";} cerr << "]";}
template<typename T>
using ordered_set = tree<T, null_type, less<T>, rb_tree_tag, tree_order_statistics_node_update>;
const int MOD=1e9+7;
const int N=1e6+10;;
const ll INF=1e16;
const long long int LINF=LLONG_MAX;
/*------------------------------------*/
void solve(int tc = 0)
{
ll k,n;input(k,n);
if(k==1){
ll ans = 0;
vll arr;
for(int i=0;i<n;i++){
char a,b;ll x,y;input(a,x,b,y);
if(a==b){
ans += abs(x-y);
}
else{
arr.pb(x);arr.pb(y);
ans++;
}
}
sort(all(arr));
if(si(arr)==0){
print(ans);return;
}
ll med = arr[(si(arr)-1)/2];
for(auto el:arr){
ans += abs(med-el);
}
print(ans);
}
else{
ll same = 0;
vll arr1,arr2;vector<pair<ll,ll>> arr3;
for(int i=0;i<n;i++){
char a,b;ll x,y;input(a,x,b,y);
if(a==b){
same += abs(x-y);
}
else{
if(a=='A')arr1.pb(x);
else arr2.pb(x);
if(b=='B')arr2.pb(y);
else arr1.pb(y);
same++;
arr3.pb({x,y});
}
}
if(si(arr3) == 0){
print(same);return;
}
sort(all(arr3),[&](pair<ll,ll> &a,pair<ll,ll> &b){
return (a.ff+a.ss)/2 < (b.ff+b.ss)/2;
});
priority_queue<ll> lpq;
priority_queue<ll,vector<ll>,greater<ll>> rpq;
ll lsum = 0,rsum = 0;
auto insert = [&](ll x){
ll med = (lpq.size()?lpq.top():INF);
if(x <= med){
lpq.push(x);lsum += x;
}
else{
rpq.push(x);rsum += x;
}
if(rpq.size() + 1 < lpq.size()){
ll curr = lpq.top();lpq.pop();
lsum -= curr;
rpq.push(curr);rsum += curr;
}
else if(rpq.size() > lpq.size()){
ll curr = rpq.top();rpq.pop();
rsum -= curr;
lpq.push(curr);lsum += curr;
}
};
n = si(arr3);vll pref(n);
for(int i=0;i<n;i++){
auto [x,y] = arr3[i];
insert(x);insert(y);
pref[i] = rsum - lsum;
}
while(lpq.size())lpq.pop();
while(rpq.size())rpq.pop();
rsum = 0;lsum = 0;ll sum = pref[n-1];
for(int i=n-1;i>0;i--){
auto [x,y] = arr3[i];
insert(x);insert(y);
sum = min(sum,rsum - lsum + pref[i-1]);
}
print(sum + same);
}
}
/*------------------------------------*/
int main()
{
#ifndef ONLINE_JUDGE
freopen("Error.txt","w",stderr);
#endif
ios_base::sync_with_stdio(false);
cin.tie(nullptr); cout.tie(nullptr);
ll tc=1;
for(int i=0 ; i < tc ; i++)
{
solve(i);
}
return 0;
}
