#include <bits/stdc++.h>
#include <ext/pb_ds/assoc_container.hpp>
#include <ext/pb_ds/tree_policy.hpp>
using namespace std;
using namespace __gnu_pbds;
using ll = long long;
template <typename T>
using ordered_set = tree<T, null_type, less<T>, rb_tree_tag, tree_order_statistics_node_update>;
vector<pair<ll, ll> > f;
void update(int i, ll v) {
++i;
while(i < f.size()) {
f[i].first += v;
++f[i].second;
i += i & -i;
}
}
pair<ll, ll> query(int l, int r) {
pair<ll, ll> ret = {0, 0};
if(l > r) return ret;
for(int i = r+1; i > 0; i -= i & -i)
ret.first += f[i].first, ret.second += f[i].second;
for(int i = l; i > 0; i -= i & -i)
ret.first -= f[i].first, ret.second -= f[i].second;
return ret;
}
int k, n;
ll ans;
vector<pair<int, int> > a;
vector<int> vals, sums;
unordered_map<int, int> mp;
vector<ll> solve(function<bool(int,int)> comp) { // comparator
vector<ll> res;
ordered_set<pair<int,int> > oset;
res.resize(sums.size());
f.assign(vals.size() + 1, make_pair(0, 0));
for(int i = 0, j = 0; i < sums.size(); i++) {
while(j < a.size() && comp(a[j].first + a[j].second, sums[i])) {
oset.insert(make_pair(a[j].first, j << 1));
oset.insert(make_pair(a[j].second, j << 1 | 1));
update(mp[a[j].first], a[j].first);
update(mp[a[j].second], a[j].second);
++j;
}
int place_first = mp[oset.find_by_order(oset.size() >> 1)->first];
ll sum, cnt;
tie(sum, cnt) = query(place_first, vals.size()-1);
res[i] += sum - cnt * vals[place_first];
tie(sum, cnt) = query(0, place_first);
res[i] += cnt * vals[place_first] - sum;
}
return res;
}
int main() {
ios::sync_with_stdio(false);
cin.tie(0);
cin >> k >> n;
for(int i = 0; i < n; i++) {
char P, Q; int s, t;
cin >> P >> s >> Q >> t;
if(P == Q) ans += abs(s-t);
else {
a.emplace_back(s, t);
vals.push_back(s);
vals.push_back(t);
sums.push_back(s+t);
}
}
ans += a.size();
if(a.empty()) {
cout << ans;
return 0;
}
sort(a.begin(), a.end(), [] (auto x, auto y) { return x.first + x.second < y.first + y.second; });
sort(sums.begin(), sums.end());
sums.resize(unique(sums.begin(), sums.end()) - sums.begin());
sort(vals.begin(), vals.end());
vals.resize(unique(vals.begin(), vals.end()) - vals.begin());
for(int i = 0; i < vals.size(); i++) mp[vals[i]] = i;
vector<ll> res1 = solve(less_equal<int>());
if(k == 1) {
ans += res1[sums.size()-1];
cout << ans;
return 0;
}
reverse(a.begin(), a.end());
reverse(sums.begin(), sums.end());
vector<ll> res2 = solve(greater<int>());
vector<ll> res = vector<ll>(sums.size());
for(int i = 0; i < sums.size(); i++) res[i] = res1[i] + res2[sums.size()-1-i];
// for(ll x: res1) cout << x << ' ';
// cout << endl;
// for(ll x: res2) cout << x << ' ';
// cout << endl;
ans += *min_element(res.begin(), res.end());
cout << ans;
}
