#include <bits/stdc++.h>
#define nl '\n'
signed main() {
std::ios::sync_with_stdio(false);
std::cin.tie(nullptr);
int theta, n;
std::cin >> theta >> n;
if (theta == 1) {
std::vector<int> x_vals;
int64_t ans = 0;
for (int i = 0; i < n; i++) {
char p, q;
int s, t;
std::cin >> p >> s >> q >> t;
if (p == q) {
ans += std::abs(t - s);
} else {
x_vals.push_back(s);
x_vals.push_back(t);
ans++;
}
}
std::sort(x_vals.begin(), x_vals.end());
int med = x_vals.size() / 2;
for (int i = 0; i < (int)x_vals.size(); i++) {
ans += std::abs(x_vals[i] - x_vals[med]);
}
std::cout << ans << nl;
return 0;
}
std::vector<int> xs;
std::vector<std::pair<int, int>> peoples;
int64_t obvious = 0;
for (int i = 0; i < n; i++) {
char p, q;
int s, t;
std::cin >> p >> s >> q >> t;
if (p == q) {
obvious += std::abs(t - s);
} else {
if (s > t) std::swap(s, t);
xs.push_back(s);
xs.push_back(t);
peoples.emplace_back(s, t);
}
}
n = peoples.size();
std::sort(xs.begin(), xs.end());
xs.erase(std::unique(xs.begin(), xs.end()), xs.end());
int sz = xs.size();
int64_t final_ans = 1e18;
for (int i = 0; i < sz; i++) {
for (int j = i + 1; j < sz; j++) {
int64_t cand = 0;
for (int k = 0; k < n; k++) {
int64_t d1 = std::abs(peoples[k].first - xs[i]);
d1 += std::abs(peoples[k].second - xs[i]);
int64_t d2 = std::abs(peoples[k].first - xs[j]);
d2 += std::abs(peoples[k].second - xs[j]);
cand += std::min(d1, d2);
}
final_ans = std::min(final_ans, cand);
}
}
std::cout << final_ans + n + obvious << nl;
}
/*
1 5
B 0 A 4
B 1 B 3
A 5 B 7
B 2 A 6
B 1 A 7
2 5
B 0 A 4
B 1 B 3
A 5 B 7
B 2 A 6
B 1 A 7
*/
