#include <bits/stdc++.h>
// #pragma GCC optimize ("O2,unroll-loops")
// #pragma GCC optimize("no-stack-protector,fast-math")
// #pragma GCC target("sse,sse2,sse3,ssse3,sse4,popcnt,abm,mmx,avx,tune=native")
#define IOS ios::sync_with_stdio(0), cin.tie(), cout.tie();
#define fr first
#define sc second
#define all(v) v.begin(), v.end()
#define uni(v) sort(all(v)), v.erase(unique(all(v)), v.end())
// #define c0 (v << 1)
// #define c1 (c0 | 1)
// #define md ((l+r)>>1)
using namespace std;
typedef long long ll;
const int maxN = 2e5+7;
int k, n, sz;
ll fix;
vector<pair<int, int>> ed;
vector<int> df;
map<int, int> mp;
int demp[maxN];
pair<int, int> pr[maxN];
vector<int> st[maxN], en[maxN];
ll dis(pair<int, int> a, ll p){
return abs(a.fr-p)+abs(a.sc-p)+1;
}
int sumer(pair<int, int> a){
return a.fr+a.sc;
}
int sumer(int a, int b){
return a+b;
}
signed main(){IOS
cin >> k >> n;
for(int i = 0; i < n; i++){
char t1, t2;
int x1, x2;
cin >> t1 >> x1 >> t2 >> x2;
if(t1 == t2){
fix += abs(x2-x1);
}
else{
ed.push_back({min(x1, x2), max(x1, x2)});
df.push_back(x1);
df.push_back(x2);
}
}
n = ed.size();
uni(df);
sz = df.size();
if(sz == 1){
cout << 0 << '\n';
return 0;
}
for(int i = 0; i < sz; i++)mp[df[i]] = i, demp[i] = df[i];
for(int i = 0; i < n; i++){
ed[i].fr = mp[ed[i].fr];
ed[i].sc = mp[ed[i].sc];
pr[i] = {ed[i].fr, ed[i].sc};
st[ed[i].fr].push_back(i);
en[ed[i].sc].push_back(i);
}
if(k == 1){
int po = 0;
ll now = 0;
int l = en[po].size(), r = n-st[po].size();
for(int i = 0; i < n; i++){
ll x = dis({demp[ed[i].fr], demp[ed[i].sc]}, demp[po]);
now += x;
}
ll ans = now;
while(po+1 < sz){
ll delt = demp[po+1]-demp[po];
now += (l*2-r*2)*delt;
ans = min(ans, now);
po++;
l += en[po].size();
r -= st[po].size();
}
cout << fix+ans << '\n';
return 0;
}
int po = 0, qo = 0;
ll now = 0;
int l0 = en[po].size(), l1 = 0, r0 = 0, r1 = n-st[po].size();
for(int i = 0; i < n; i++){
ll x = dis({demp[ed[i].fr], demp[ed[i].sc]}, demp[po]);
now += x;
}
ll ans = now;
priority_queue<pair<int, int>> pq;
while(po+1 < sz){
ll delt = demp[po+1]-demp[po];
now -= (r1-r0)*delt*2;
ans = min(ans, now);
po++;
r1 -= st[po].size();
r0 += en[po].size();
for(auto i : en[po]){
pq.push({-sumer(pr[i]), i});
}
while(pq.size() && -pq.top().fr <= po+qo){
r0--;
l1++;
pq.pop();
}
while(qo+1 < po){
ll delt = demp[qo+1]-demp[qo];
ll nxt = now;
nxt -= (l1-l0)*delt*2;
if(nxt > now)break;
qo++;
while(pq.size() && -pq.top().fr <= po+qo){
r0--;
l1++;
pq.pop();
}
for(auto i : st[qo]){
if(pr[i].sc <= po)l1--;
}
l0 += en[qo].size();
}
}
cout << fix+ans << '\n';
}
/*
1 5
B 0 A 4
B 1 B 3
A 5 B 7
B 2 A 6
B 1 A 7
===
24
===
2 5
B 0 A 4
B 1 B 3
A 5 B 7
B 2 A 6
B 1 A 7
===
22
===
*/
