#include <bits/stdc++.h>
using namespace std;
using lint = long long;
int K, N;
lint ans;
vector<pair<lint, lint>> A;
lint solve_1() {
array<vector<lint>, 2> prefix_sum;
vector<lint> points;
prefix_sum[0].resize(A.size());
prefix_sum[1].resize(A.size());
for (int i = 0; i < N; i++) {
prefix_sum[0][i] = ((i > 0)? prefix_sum[0][i - 1] : 0) + A[i].first;
prefix_sum[1][i] = ((i > 0)? prefix_sum[1][i - 1] : 0) + A[i].second;
points.emplace_back(A[i].first);
points.emplace_back(A[i].second);
}
lint res = INT64_MAX;
for (auto p : points) {
lint fi = upper_bound(prefix_sum[0].begin(), prefix_sum[0].end(), p) - prefix_sum[0].begin() - 1;
lint se = upper_bound(prefix_sum[1].begin(), prefix_sum[1].end(), p) - prefix_sum[1].begin() - 1;
lint tmp1 = ((fi + 1) * p - (fi >= 0? prefix_sum[0][fi] : 0)) + ((prefix_sum[0][N - 1] - (fi >= 0? prefix_sum[0][fi] : 0)) - (N - fi - 1) * p);
lint tmp2 = ((se + 1) * p - (se >= 0? prefix_sum[1][se] : 0)) + ((prefix_sum[1][N - 1] - (se >= 0? prefix_sum[1][se] : 0)) - (N - se - 1) * p);
res = min(res, tmp1 + tmp2);
}
return res;
}
lint solve_2() {
auto get = [&](lint B1, lint B2) {
lint res = 0;
for (int i = 0; i < N; i++) {
res += min(labs(B1 - A[i].first) + labs(B1 - A[i].second),
labs(B2 - A[i].first) + labs(B2 - A[i].second));
}
return res;
};
lint res = INT64_MAX;
vector<lint> points;
for (int i = 0; i < N; i++)
points.emplace_back(A[i].first), points.emplace_back(A[i].second);
sort(points.begin(), points.end());
points.resize(unique(points.begin(), points.end()) - points.begin());
for (int i = 0; i < points.size(); i++) {
int le = i + 1, ri = points.size() - 1;
while (le <= ri) {
int mid = (le + ri) / 2;
if (mid + 1 >= N) {
ri--;
continue;
} else if (mid < 0) {
le++;
continue;
} else {
lint l = get(i, mid), r = get(i, mid + 1);
res = min(res, l), res = min(res, r);
if (l < r) {
ri = mid;
} else {
le = mid + 1;
}
}
}
}
return res;
}
lint solve() {
sort(A.begin(), A.end());
N = A.size();
if (K == 1)
return N + solve_1();
else
return N + solve_2();
}
int main() {
ios_base::sync_with_stdio(0);
cin.tie(0);
cin >> K >> N;
for (int i = 0; i < N; i++) {
char Z1, Z2;
lint B1, B2;
cin >> Z1 >> B1 >> Z2 >> B2;
if (B1 > B2) swap(B1, B2);
if (Z1 == Z2)
ans += B2 - B1;
else
A.emplace_back(B1, B2);
}
ans += solve();
cout << ans << "\n";
return 0;
}
