#include <bits/stdc++.h>

using namespace std;
#define int long long

signed main() {
    ios_base::sync_with_stdio(false);
    cin.tie(nullptr), cout.tie(nullptr);
    int k, n;
    cin >> k >> n;
    char p[n], q[n];
    int s[n], t[n];
    for (int i = 0; i < n; i++) cin >> p[i] >> s[i] >> q[i] >> t[i];
    int res = (int) 1e18;
    set<int> all;
    for (int i = 0; i < n; i++) {
        if (s[i] < t[i]) swap(s[i], t[i]);
        all.insert(t[i]), all.insert(s[i]);
    }
    for (int x: all) {
        int cur_res = 0;
        for (int i = 0; i < n; i++) {
            if (p[i] == q[i]) {
                cur_res += s[i] - t[i];
                continue;
            }
            if (x < t[i]) cur_res += t[i] - x + s[i] - x + 1;
            else if (x > s[i]) cur_res += x - s[i] + x - t[i] + 1;
            else cur_res += s[i] - t[i] + 1;
        }
        res = min(res, cur_res);
    }
    cout << res;
    return 0;
}