#include <bits/stdc++.h>
using namespace std;
#define int long long
const int INF = 1e18;
int sumlow = 0, sumhigh = 0;
multiset<int> low, high;
void sinsert(int val) {
int med = low.empty() ? INF : *low.rbegin();
if (val > med) {
high.insert(val);
sumhigh += val;
} else {
low.insert(val);
sumlow += val;
}
if (high.size() > low.size()) {
int tmp = *high.begin();
low.insert(tmp);
sumlow += tmp;
sumhigh -= tmp;
high.erase(high.find(tmp));
} else if (low.size() > high.size() + 1) {
int tmp = *low.rbegin();
high.insert(tmp);
sumhigh += tmp;
sumlow -= tmp;
low.erase(low.find(tmp));
}
}
signed main() {
ios::sync_with_stdio(0);
cin.tie(0);
int k, n;
cin >> k >> n;
vector<pair<int, int>> diff;
int same = 0;
for (int i = 0; i < n; i++) {
char p, q;
int s, t;
cin >> p >> s >> q >> t;
if (p == q) {
same += abs(s - t);
} else {
if (s > t) swap(s, t);
diff.push_back({s, t});
}
}
sort(diff.begin(), diff.end(), [](const pair<int, int>& a, const pair<int, int>& b) {
return a.first + a.second < b.first + b.second;
});
int sz = diff.size();
same += sz; // crossing the river
vector<int> precal(sz);
if (sz == 0) {
cout << same;
return 0;
}
for (int i = 0; i < sz; i++) {
sinsert(diff[i].first);
sinsert(diff[i].second);
int med = *low.rbegin();
precal[i] = (med * (int)low.size() - sumlow) + (sumhigh - med * (int)high.size());
}
if (k == 1) {
int med = *low.rbegin();
int ans = (med * (int)low.size() - sumlow) + (sumhigh - med * (int)high.size());
cout << same + ans;
return 0;
}
sumlow = sumhigh = 0;
low.clear(); high.clear();
int ans = precal[sz - 1];
// since we precalculated from the beginning, we loop back from the end
for (int i = sz - 1; i >= 1; i--) {
sinsert(diff[i].first);
sinsert(diff[i].second);
int med = *low.rbegin();
int val = (med * (int)low.size() - sumlow) + (sumhigh - med * (int)high.size());
ans = min(ans, val + precal[i - 1]);
}
cout << same + ans;
}
/*
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
*/
