#include<bits/stdc++.h>
#pragma optimize ("g",on)
#pragma GCC optimize ("inline")
#pragma GCC optimize ("Ofast")
#pragma GCC optimize ("unroll-loops")
#pragma GCC optimize ("03")
#pragma GCC target ("sse,sse2,sse3,ssse3,sse4,popcnt,abm,avx2,mmx,fma,avx,tune=native")
//01001101 01100001 01101011 01101000 01100001 01100111 01100001 01111001
using namespace std;
#define all(a) a.begin(), a.end()
#define rall(a) a.rbegin(), a.rend()
#define ll long long
#define pb push_back
#define sz(a) a.size()
#define nl '\n'
#define popb pop_back()
#define ld double
#define ull unsigned long long
#define ff first
#define ss second
#define fix fixed << setprecision
#define pii pair<int, int>
#define E exit (0)
#define int long long
const int inf = 1e15, N = 5e3 + 1, mod = 998244353;
double eps = 1e-6;
vector<pii> dir = {{1, 0}, {0, 1}, {-1, 0}, {0, -1}};
main() {
//freopen("F.in", "r", stdin);
//freopen("F.out", "w", stdout);
ios_base::sync_with_stdio(NULL);
cin.tie(NULL);
int k, n;
cin >> k >> n;
char t1[n + 1], t2[n + 1];
int p1[n + 1], p2[n + 1];
for (int i = 1; i <= n; i++) {
cin >> t1[i] >> p1[i] >> t2[i] >> p2[i];
}
if (k == 1) {
vector<int> s;
for (int i = 1; i <= n; i++) {
if (t1[i] != t2[i]) {
s.pb(p1[i]);
s.pb(p2[i]);
}
}
sort(all(s));
int p = -1;
if (sz(s)) p = s[sz(s) / 2];
int ans = inf;
for (int i = -100; i <= 100; i++) {
p += i;
int cur = 0;
for (int j = 1; j <= n; j++) {
if (t1[j] == t2[j]) {
cur += abs(p2[j] - p1[j]);
continue;
}
cur += abs(p1[j] - p) + abs(p2[j] - p) + 1;
}
p -= i;
ans = min(ans, cur);
}
cout << ans;
}else {
vector<pii> s;
int val = 0;
for (int i = 1; i <= n; i++) {
val += abs(p2[i] - p1[i]);
if (t1[i] != t2[i]) {
val++;
s.pb({p1[i], i});
s.pb({p2[i], i});
}
}
sort(all(s));
int suf[sz(s) + 1];
suf[sz(s)] = 0;
int cnt = 0, ans = inf;
vector<int> was(n + 1);
for (int i = sz(s) - 1; i >= 0; i--) {
suf[i] = suf[i + 1] + 2 * cnt;
if (was[s[i].ss]) {
cnt++;
}
was[s[i].ss] = 1;
}
cnt = 0;
for (int i = 0; i <= n; i++) was[i] = 0;
int cur = 0, last = 0;
for (int i = 0; i < sz(s); i++) {
cur += 2 * cnt * (s[i].ff - last);
if (was[s[i].ss]) {
cnt++;
}
last = s[i].ff;
was[s[i].ss] = 1;
int cnt2 = 0, cur2 = 0, last2 = 0;
vector<int> was2(n + 1);
for (int j = i + 1; j < sz(s); j++) {
cur2 += 2 * cnt2 * (s[j].ff - last2);
if (was2[s[j].ss]) {
cnt2++;
}
last2 = s[j].ff;
was2[s[j].ss] = 1;
ans = min(ans, cur + cur2 + suf[j + 1] + val);
}
}
cout << ans;
}
}
