#include<bits/stdc++.h>
using namespace std;
#define ll long long
#define FOR(i, a, b) for (int i = (a), _b = (b); i <= _b; i++)
#define FORD(i, b, a) for (int i = (b), _a = (a); i >= _a; i--)
#define pa pair<ll, ll>
#define fi first
#define se second
#define bit(mask, j) ((mask >> j) & 1)
const ll mod = 1e9 + 7;
const ll INF = 1e18;
//--------------------------------------------------------------------
ll ans = INF;
ll cur = 0, sum = 0;
const ll N = 1e5 + 10;
vector<ll> event;
pair<ll, pa> a[N];
ll o = 0;
multiset<ll> stl1, stl2, str1, str2;
void hbmt() {
ll k, n;
cin >> k >> n;
if(k == 2) {
FOR(i, 1, n) {
ll s, t;
char p, q;
cin >> p >> s >> q >> t;
if(p == q) {
cur += abs(s - t);
}
else {
if(s > t) swap(s, t);
a[++o] = {s + t, {s, t}};
}
}
sort(a + 1, a + o + 1);
ll mid_pre = -1;
ll res = 0;
ll mid_pre2 = 0, res2 = 0;
FOR(i, 1, o) {
str1.insert(a[i].se.fi);
str1.insert(a[i].se.se);
}
while(str1.size() > str2.size()) {
ll x = *str1.rbegin();
str2.insert(x);
str1.erase(str1.find(x));
}
mid_pre2 = *str1.rbegin();
FOR(i, 1, o) {
res2 += abs(a[i].se.fi - mid_pre2) + abs(a[i].se.se - mid_pre2);
}
ans = res2 + cur + o;
FOR(i, 1, o) {
assert(stl1.size() == stl2.size());
if(!stl1.empty() && *stl1.rbegin() < a[i].se.fi) {
stl2.insert(a[i].se.fi);
}
else stl1.insert(a[i].se.fi);
if(!stl1.empty() && *stl1.rbegin() < a[i].se.se) {
stl2.insert(a[i].se.se);
}
else stl1.insert(a[i].se.se);
while(stl1.size() < stl2.size()) {
ll x = *stl2.begin();
stl1.insert(x);
stl2.erase(stl2.find(x));
}
while(stl1.size() > stl2.size()) {
ll x = *stl1.rbegin();
stl2.insert(x);
stl1.erase(stl1.find(x));
}
if(str1.find(a[i].se.fi) != str1.end()) {
str1.erase(str1.find(a[i].se.fi));
}
else if(str2.find(a[i].se.fi) != str2.end()) {
str2.erase(str2.find(a[i].se.fi));
}
if(str1.find(a[i].se.se) != str1.end()) {
str1.erase(str1.find(a[i].se.se));
}
else if(str2.find(a[i].se.se) != str2.end()) {
str2.erase(str2.find(a[i].se.se));
}
while(str1.size() < str2.size()) {
ll x = *str2.begin();
str1.insert(x);
str2.erase(str2.find(x));
}
while(str1.size() > str2.size()) {
ll x = *str1.rbegin();
str2.insert(x);
str1.erase(str1.find(x));
}
ll mid_new = *stl1.rbegin();
res += abs(mid_new - a[i].se.fi) + abs(mid_new - a[i].se.se);
if(mid_new != mid_pre && mid_pre != -1) {
if(mid_new < mid_pre) {
res = res - stl1.size() * (mid_pre - mid_new) + stl2.size() * (mid_pre - mid_new);
}
else {
res = res + stl1.size() * (mid_new - mid_pre) - stl2.size() * (mid_new - mid_pre);
}
}
if(str1.size() == 0) {
ans = min(ans, cur + res + (ll)stl1.size());
break;
}
ll mid_new2 = *str1.rbegin();
res2 -= abs(mid_pre2 - a[i].se.fi) + abs(mid_pre2 - a[i].se.se);
if(mid_new2 != mid_pre2) {
if(mid_pre2 < mid_new2) {
res2 = res2 + (str1.size() - 1) * (mid_new2 - mid_pre2) - (str2.size() + 1) * (mid_new2 - mid_pre2);
}
else {
res2 = res2 - str1.size() * (mid_pre2 - mid_new2) + str2.size() * (mid_pre2 - mid_new2);
}
}
ans = min(ans, cur + res2 + res + (ll)str1.size() + (ll)stl1.size());
mid_pre = mid_new;
mid_pre2 = mid_new2;
// cout <<res << ' ' << res2 << "\n\n";
}
cout << ans;
return;
}
assert(k == 1);
FOR(i, 1, n) {
ll s,t ;
char p, q;
cin >> p >> s >> q >> t;
if(p == q) {
cur += abs(s - t);
}
else {
event.push_back(s);
event.push_back(t);
}
}
sort(event.begin(), event.end());
FOR(i, 1, event.size() - 1) {
sum += event[i] - event[0];
}
ans = sum + cur;
ll sz = event.size();
FOR(i, 1, event.size() - 1) {
ll w = event[i] - event[i - 1];
sum = sum + (w * i) - (w * (sz - (i)));
ans = min(sum + cur, ans);
}
cout << ans + sz / 2;
}
int main() {
ios_base::sync_with_stdio(0);
cin.tie(0);cout.tie(0);
#define NAME "hbmt"
if(fopen(NAME".inp", "r")) {
freopen(NAME".inp", "r", stdin);
freopen(NAME".ans", "w", stdout);
}
//int t;cin>>t;while(t--)
hbmt();
return 0;
}
