#include <bits/stdc++.h>
using namespace std;
using ll = long long;
using ld = long double;
#define int long long int
ll MOD = 1e9 + 7;
priority_queue<int, vector<int>, greater<int>> min_heap;
priority_queue<int> max_heap;
int mx, mn;
void insert(int x) {
int median = (max_heap.size() ? max_heap.top() : 1000000001);
if(x <= median) {
max_heap.push(x);
mx += x;
}
else {
min_heap.push(x);
mn += x;
}
if(min_heap.size() + 1 < max_heap.size()) {
int change = max_heap.top();
mx -= change;
mn += change;
max_heap.pop();
min_heap.push(change);
} else if(max_heap.size() < min_heap.size()) {
int change = min_heap.top();
mn -= change;
mx += change;
min_heap.pop();
max_heap.push(change);
}
}
void solve() {
int k, n;
cin >> k >> n;
int dist = 0;
vector<pair<int, int>> v = {{0, 0}};
for(int i = 0; i < n; i++) {
char a, b; int c, d;
cin >> a >> c >> b >> d;
if(a == b) dist += abs(c - d);
else v.push_back({c, d});
}
sort(v.begin(), v.end(), [](auto const& a, auto const& b) {
return a.first + a.second < b.first + b.second;
});
n = v.size() - 1;
dist += n;
mx = mn = 0;
vector<int> prefix(n + 1);
for(int i = 1; i <= n; i++) {
insert(v[i].first);
insert(v[i].second);
prefix[i] += mn - mx;
}
int ans = prefix[n];
if(k == 2) {
while(max_heap.size()) max_heap.pop();
while(min_heap.size()) min_heap.pop();
mx = mn = 0;
for(int i = n; i > 0; i--) {
insert(v[i].first);
insert(v[i].second);
ans = min(ans, prefix[i - 1] + mn - mx);
}
}
cout << dist + ans;
}
int32_t main() {
ios_base::sync_with_stdio(false);
cin.tie(NULL);
cout.tie(NULL);
solve();
}
