// fest
#include <bits/stdc++.h>
#define pb push_back
#define F first
#define S second
#define y1 dasdasfasfas
#define x1 wqdadfasfasfas
#define All(c) c.begin(), c.end()
#define SZ(A) (int((A).size()))
#define umap unordered_map
#define FILENAME ""
#define __ fflush(stdout)
typedef long long ll;
typedef long double ld;
using namespace std;
void FREOPEN() {
#ifdef COMP
freopen(".in", "r", stdin);
freopen("2.out", "w", stdout);
#else
freopen(FILENAME".in", "r", stdin);
freopen(FILENAME".out", "w", stdout);
#endif
}
inline double Time() {return (clock() * 1.0) / CLOCKS_PER_SEC; }
const int N = 200500, inf = 1e9 + 1, MOD = (int)1e9 + 7;
char CH[N];
const ll INF = 1e18;
const int dx[] = {1, -1, 0, 0, -1, 1, -1, 1};
const int dy[] = {0, 0, 1, -1, -1, 1, 1, -1};
vector<pair<int, int> > all;
ll calc(int x, int y) {
ll ret = 0;
for (auto i : all) {
ret += min(abs(i.F - x) + abs(i.S - x), abs(i.F - y) + abs(i.S - y));
}
return ret;
}
ll check(int k, int p) {
if (k == 1) return calc(p, p);
int l = 0;
int r = inf;
while (r - l > 1) {
int mid = (l + r) / 2;
if (calc(p, mid) > calc(p, mid + 1)) l = mid;
else r = mid;
}
return min(calc(p, l), calc(p, r));
}
int main() {
int k, n;
cin >> k >> n;
ll un = 0;
for (int i = 1; i <= n; i++) {
char t1, t2;
int p1, p2;
scanf("\n%c %d %c %d", &t1, &p1, &t2, &p2);
if (t2 == 'A') swap(t1, t2), swap(p1, p2);
if (t1 == t2) {
un += abs(p2 - p1);
continue;
}
all.pb({p1, p2});
}
if (k == 1) {
int l = 0;
int r = inf;
while (r - l > 1) {
int mid = (l + r) / 2;
if (check(k, mid) > check(k, mid + 1)) l = mid;
else r = mid;
}
cout << un + SZ(all) + min(check(k, l), check(k, r));
return 0;
}
ll mn = INF;
for (auto i : all) {
for (auto j : all) {
mn = min(mn, calc(i.F, j.F));
mn = min(mn, calc(i.F, j.S));
mn = min(mn, calc(i.S, j.F));
mn = min(mn, calc(i.S, j.S));
}
}
cout << mn + un + SZ(all);
return 0;
}
