#include <bits/stdc++.h>
using namespace std;
typedef long long ll;
#define int ll
#define pb push_back
typedef pair<int, int> pii;
#define F first
#define S second
#define len(x) (int)(x).size()
const int INF = 1e18;
bool cmin(int &a, const int &b) {
if (a > b) {
a = b;
return 1;
}
return 0;
}
void run() {
int k, n;
cin >> k >> n;
int ans = 0;
vector<pii> v;
vector<int> vals;
for (int i = 0; i < n; ++i) {
char a, c;
int b, d;
cin >> a >> b >> c >> d;
a -= 'A';
c -= 'A';
if (a == c) {
ans += abs(b - d);
} else {
if (a)
swap(b, d);
v.pb({b, d});
vals.pb(b);
vals.pb(d);
}
}
int ans2 = INF;
if (len(vals) == 0)
ans2 = 0;
for (auto x : vals) {
int cur_ans2 = 0;
for (auto f : v) {
cur_ans2 += abs(f.F - x) + abs(f.S - x) + 1;
}
cmin(ans2, cur_ans2);
}
// cout << ans << ' ' << ans2 << '\n';
cout << ans + ans2 << '\n';
}
signed main() {
ios_base::sync_with_stdio(0);
cin.tie(0);
cout.tie(0);
run();
}
