#include<bits/stdc++.h>
using namespace std;
void solve(){
int k, n, a, b;cin >> k >> n;
char c,h;
long long sl = 0, ans = LONG_LONG_MAX, cur = 0, tans = 0;
vector<pair<int, int>> e;
if(k == 1){
while(n--){
cin >> c >> a >> h >> b;
if(a>b)swap(a,b);
tans += b-a;
if(c==h) continue;
tans++;
e.emplace_back(a, false);
e.emplace_back(b, true);
}
if(e.empty()){
cout << tans << '\n';
return;
}
sort(e.begin(), e.end());
for(int i = 0;i < e.size();i++){
if(!e[i].second) {
sl -= 2;
cur += 2*(e[i].first-e[0].first);
}
}
int pr = e[0].first;
for(auto p : e){
cur += sl*(p.first-pr);
pr = p.first;
ans = min(ans, cur);
sl += 2;
}
cout << ans+tans << '\n';
return;
}
for(int i = 0;i < n;i++){
cin >> c >> a >> h >> b;
if(a>b)swap(a,b);
tans += b-a;
if(c==h) continue;
tans++;
e.emplace_back(a, -i-1);
e.emplace_back(b, i+1);
}
if(e.empty()){
cout << tans << '\n';
return;
}
sort(e.begin(), e.end());
int pr = e[0].first;
for(auto p : e){
cur += sl*(p.first-pr);
pr = p.first;
if(p.second > 0) sl += 2;
vector<pair<int, int>> g;
int v[n+1];fill(v, v+n+1, -1);
long long slope = 0, CUR = 0;
for(auto pp : e){
if(pp.first <= p.first) continue;
if(pp.second < 0){
CUR += 2*(pp.first-p.first);
slope -= 2;
g.emplace_back(pp.first, 2);
v[-pp.second] = pp.first-p.first;
} else if(v[pp.second] != -1){
g.emplace_back(pp.first, 2);
g.emplace_back(pp.first+v[pp.second], -2);
}
}
if(g.empty()){
ans = min(ans, cur);
continue;
}
sort(g.begin(), g.end());
int pre = p.first;
for(auto pp : g){
CUR += slope*(pp.first-pre);
pre = pp.first;
ans = min(ans, cur+CUR);
slope += pp.second;
}
}
cout << ans+tans << '\n';
}
int main(){
ios_base::sync_with_stdio(false);
cin.tie(0);
solve();
}
