#include<deque>
#include<queue>
#include<vector>
#include<algorithm>
#include<iostream>
#include<set>
#include<cmath>
#include<tuple>
#include<string>
#include<chrono>
#include<functional>
#include<iterator>
#include<random>
#include<unordered_set>
#include<unordered_map>
#include<array>
#include<map>
#include<bitset>
#include<iomanip>
#include<list>
#include <numeric>
using namespace std;
typedef unsigned long long int ulint;
typedef long long int llint;
typedef long double lldo;
#define mp make_pair
#define mt make_tuple
#define pub push_back
#define puf push_front
#define pob pop_back
#define pof pop_front
#define fir first
#define sec second
#define res resize
#define ins insert
#define era erase
#define RE return 0
//ios::sync_with_stdio(false);
//std::cin.tie(0);
//<< setprecision(20)
const int mod=(int)1e9+7;
const llint big=(llint)(2.19e15+1);
const long double pai=3.141592653589793238462643383279502884197;
const long double ena=2.71828182845904523536;
const long double eps=1e-7;
template <class T,class U>bool mineq(T& a,U b){if(a>b){a=b;return true;}return false;}
template <class T,class U>bool maxeq(T& a,U b){if(a<b){a=b;return true;}return false;}
template <class T> void soun(T& ar)
{sort(ar.begin(),ar.end());ar.erase(unique(ar.begin(),ar.end()),ar.end());}
llint gcd(llint a,llint b){if(a%b==0){return b;}else{return gcd(b,a%b);}}
llint lcm(llint a,llint b){return a/gcd(a,b) *b;}
template<class T,class U> auto LB(T& ve,U in){return lower_bound(ve.begin(),ve.end(),in);}
template<class T,class U> auto UB(T& ve,U in){return upper_bound(ve.begin(),ve.end(),in);}
template<class T,class U> auto LBI(T& ve,U in){return LB(ve,in)-ve.begin();}
template<class T,class U> auto UBI(T& ve,U in){return UB(ve,in)-ve.begin();}
template<class T> void SO(T& ve){sort(ve.begin(),ve.end());}
template<class T> void REV(T& ve){reverse(ve.begin(),ve.end());}
int main(void){
int K,n,i;cin>>K>>n;
if(K==1){
//ieのあるところしか橋を造らない
llint ans=big,mto=0;
int m;
vector<pair<llint,llint>>ie;
//vector<llint>atu;
for(i=0;i<n;i++){
char ca,cb;int ba,bb;
cin>>ca>>ba>>cb>>bb;
if(ba>bb){swap(ba,bb);}
mto+=bb-ba;
if(ca!=cb){mto++;ie.pub(mp(ba,bb));}
}
//SO(atu);
//atu.erase(unique(atu.begin(),atu.end()),atu.end());
//m=atu.size();
n=ie.size();
vector<pair<llint,int>>house;house.reserve(n+n);
llint gen=0,num=0;
for(auto it:ie){
gen+=it.fir;num++;
house.pub(mp(it.fir,1));
house.pub(mp(it.sec,-1));
}
SO(house);
for(auto it:house){
gen-=it.fir;
num--;
mineq(ans,mto+2*(gen-num*it.fir));
//cerr<<gen-num*it.fir<<endl;
}
cout<<ans<<endl;
}
return 0;
}
