#include <bits/stdc++.h>
#pragma GCC optimize ("O2")
#pragma GCC optimize ("unroll-loops")
//#pragma GCC optimize("no-stack-protector,fast-math")
using namespace std;
typedef long long ll;
typedef long double ld;
typedef pair<int, int> pii;
typedef pair<pii, int> piii;
typedef pair<ll, ll> pll;
#define debug(x) cerr<<#x<<'='<<(x)<<endl;
#define debugp(x) cerr<<#x<<"= {"<<(x.first)<<", "<<(x.second)<<"}"<<endl;
#define debug2(x, y) cerr<<"{"<<#x<<", "<<#y<<"} = {"<<(x)<<", "<<(y)<<"}"<<endl;
#define debugv(v) {cerr<<#v<<" : ";for (auto x:v) cerr<<x<<' ';cerr<<endl;}
#define all(x) x.begin(), x.end()
#define pb push_back
#define kill(x) return cout<<x<<'\n', 0;
const ld eps=1e-7;
const int inf=1000000010;
const ll INF=10000000000000010LL;
const int mod=1000000007;
const int MAXN=100010, LOG=20;
ll n, m, k, u, v, x, y, t, l, r, ans, constant;
pll A[MAXN];
ll B[MAXN], C[MAXN];
struct Solver{
priority_queue<ll> pref;
priority_queue<ll, vector<ll>, greater<ll>> suff;
ll pref_sum=0, suff_sum=0, mid=inf;
void Add(ll x){
if (x<=mid) pref.push(x), pref_sum+=x;
else suff.push(x), suff_sum+=x;
while (pref.size()<suff.size()){
ll x=suff.top();
suff.pop();
suff_sum-=x;
pref.push(x);
pref_sum+=x;
//cerr<<"move2 "<<x<<endl;
}
while (pref.size()-suff.size()>1){
ll x=pref.top();
pref.pop();
pref_sum-=x;
suff.push(x);
suff_sum+=x;
//cerr<<"move1 "<<x<<endl;
}
mid=pref.top();
}
ll Get(){
return suff_sum-suff.size()*mid + pref.size()*mid-pref_sum;
}
} S1, S2;
int main(){
ios_base::sync_with_stdio(false);cin.tie(0);cout.tie(0);
//freopen("input.txt", "r", stdin);
//freopen("output.txt", "w", stdout);
cin>>k>>m;
//assert(m<=1000 && k==1);
char c1, c2;
while (m--){
cin>>c1>>l>>c2>>r;
if (l>r) swap(l, r);
if (c1!=c2){
A[++n]={l, r};
constant++;
}
else constant+=r-l;
}
sort(A+1, A+n+1, [](pll i, pll j){
return i.first+i.second<j.first+j.second;
});
for (int i=1; i<=n; i++){
S1.Add(A[i].first);
S1.Add(A[i].second);
B[i]=S1.Get();
}
for (int i=n; i; i--){
S2.Add(A[i].first);
S2.Add(A[i].second);
C[i]=S2.Get();
}
ans=B[n];
if (k==2){
for (int i=1; i<n; i++) ans=min(ans, B[i]+C[i+1]);
}
//debug(ans)
cout<<ans+constant<<'\n';
return 0;
}
/*
1 5
B 0 A 4
B 1 B 3
A 5 B 7
B 2 A 6
B 1 A 7
*/
