#include <bits/stdc++.h>
#include <ext/pb_ds/assoc_container.hpp>
#include <ext/pb_ds/tree_policy.hpp>
#define int long long
#define arr2 array<int, 2>
#define arr3 array<int, 3>
#define all(a) a.begin(), a.end()
#define double long double
// #pragma GCC target("avx2")
using namespace std;
using namespace __gnu_pbds;
template<class T> using rb3 = tree<T, null_type, less<T>, rb_tree_tag, tree_order_statistics_node_update>;
template<class T> using mrb3 = tree<T, null_type, less_equal<T>, rb_tree_tag, tree_order_statistics_node_update>;
const int N = 1e5 + 10, M = 998244353;
int cost = 0;
int abc(int a) {
return (a < 0 ? -a : a);
}
void fun() {
int k, n;
cin >> k >> n;
vector<int> pnt;
for (int i = 0; i < n; ++i) {
char a, c;
int b, d;
cin >> a >> b >> c >> d;
if (a == c) {
cost += abc(d - b);
}
else {
cost++;
pnt.push_back(b);
pnt.push_back(d);
}
}
sort(all(pnt));
if (pnt.size()) {
int mid = pnt[(pnt.size()) / 2];
for (int i : pnt) {
cost += abc(i - mid);
}
}
cout << cost << "\n";
}
int32_t main() {
ios::sync_with_stdio(0);
cin.tie(0); cout.tie(0);
// int tc;
// cin >> tc;
// while (tc--)
fun();
}
