#include <cstdio>
#include <iostream>
#include <cstring>
#include <algorithm>
#include <queue>
#include <vector>
using namespace std;
typedef long long LL;
const int N = 200005;
int K, n, d[N];
LL f[N], g[N];
LL ans = 0;
struct E{
	int P, S, Q, T;
	bool operator < (const E &x) const {
		return S + T < x.S + x.T;
	}
}e[N]; 
priority_queue<int> q0;
priority_queue<int, vector<int>, greater<int> > q1;
LL s0, s1;
void inline add(int x) {
	if(q0.empty() || q0.top() >= x) 
		q0.push(x), s0 += x;
	else q1.push(x), s1 += x;
	
	if(q0.size() > q1.size() + 1) {
		s0 -= q0.top(); s1 += q0.top();
		q1.push(q0.top()); q0.pop();
	} 
	if(q1.size() > q0.size()) {
		s0 += q1.top(); s1 -= q1.top();
		q0.push(q1.top()); q1.pop();
	}
}
int main(){
	scanf("%d%d", &K, &n);
	int tot = 0;
	for (int i = 1; i <= n; i++) {
		char P[2], Q[2]; int S, T;
		scanf("%s%d%s%d", P, &S, Q, &T);
		if(P[0] == Q[0]) ans += abs(T - S); 
		else e[++tot] =  (E) { P[0] - 'A', S, Q[0] - 'A', T };
	}
	n = tot;
	if(K == 1) {
		int m = 0;
		for (int i = 1; i <= n; i++){
			d[++m] = e[i].S, d[++m] = e[i].T;
		}
		sort(d + 1, d + 1 + m);
		int v = d[(m + 1) >> 1];
		for (int i = 1; i <= m; i++) {
			ans += abs(d[i] - v); 
		}
		ans += m / 2;
		printf("%lld\n", ans);
	} else {
		sort(e + 1, e + 1 + n);
		LL val = 9e18;
		s0 = s1 = 0;
		for (int i = 1; i <= n; i++) {
			add(e[i].S); add(e[i].T);
			int x = q0.top();
			f[i] = ((LL)x * q0.size() - s0) + (s1 - (LL)x * q1.size());
		}
		while(!q0.empty()) q0.pop();
		while(!q1.empty()) q1.pop();
		s0 = s1 = 0;
		for (int i = n; i; i--){
			add(e[i].S); add(e[i].T);
			int x = q0.top();
			g[i] = ((LL)x * q0.size() - s0) + (s1 - (LL)x * q1.size());
		}
		
		for (int i = 0; i <= n; i++) {
			val = min(val, f[i] + g[i + 1]);
		}
		printf("%lld\n", ans + val + n);
	} 
	return 0;
}