#include <iostream>
#include <cmath>
#include <algorithm>
#include <vector>
using namespace std;
long long N, K, Q, A[100009], B[100009], sum;
vector<long long>Z; vector<long long>S;
long long calculate() {
long long rem = 0;
for (int i = 1; i <= Q; i++) {
long long F = (1LL << 60);
for (int j = 0; j < S.size(); j++) {
if (A[i] <= S[j] && S[j] <= B[i]) F = 0;
F = min(F, 2LL * min(abs(A[i] - S[j]), abs(B[i] - S[j])));
}
rem += F;
}
return sum + rem;
}
long long solve(long long pos) {
long long rev = (1LL << 60); int i = pos;
vector<pair<long long, long long>>vec; long long R = 0;
for (int j = 1; j <= Q; j++) {
if (A[j] > Z[i]) { R += 2; vec.push_back(make_pair(A[j], 2)); vec.push_back(make_pair(B[j], 2)); vec.push_back(make_pair(B[j] + A[j] - Z[i], -2)); }
}
sort(vec.begin(), vec.end());
S = vector<long long>{ Z[i] };
long long D = calculate(), J = -R, cx = Z[i]; rev = min(rev, D);
for (int j = 0; j < vec.size(); j++) {
rev = min(rev, D);
D += J*(vec[j].first - cx);
J += vec[j].second; cx = vec[j].first;
}
return rev;
}
int main() {
cin >> K >> N;
for (int i = 1; i <= N; i++) {
char a1, b1; long long a2, b2;
cin >> a1 >> a2 >> b1 >> b2;
if (a1 == b1) sum += abs(a2 - b2);
else {
Q++; if (a2 > b2) swap(a2, b2);
A[Q] = a2; B[Q] = b2;
sum += (b2 - a2 + 1);
}
}
for (int i = 1; i <= Q; i++) { Z.push_back(A[i]); Z.push_back(B[i]); }
sort(Z.begin(), Z.end());
if (Q == 0) {
cout << sum << endl;
return 0;
}
if (K == 1) {
vector<long long>vec;
for (int i = 1; i <= Q; i++) { vec.push_back(A[i]); vec.push_back(B[i]); }
sort(vec.begin(), vec.end());
S = vector<long long>{ vec[vec.size() / 2] };
long long ans = calculate();
cout << ans << endl;
}
if (K == 2) {
long long ans = (1LL << 60);
long long L = 0, R = Z.size(), C1, C2;
for (int i = 0; i < 27; i++) {
C1 = (L + L + R) / 3;
C2 = (L + R + R) / 3;
long long v1 = solve(C1);
long long v2 = solve(C2);
ans = min(ans, min(v1, v2));
if (v1 > v2) { L = C1; }
else { R = C2; }
}
for (int i = -3; i <= 3; i++) {
if (C1 + i < 0 || C1 + i >= Z.size()) continue;
ans = min(ans, solve(C1 + i));
}
cout << ans << endl;
}
return 0;
}
