#include <bits/stdc++.h>
using namespace std;
#define rep(i, l, r) for(int i = (l), _r = (r); i < _r; ++i)
#define FOR(i, l, r) for(int i = (l), _r = (r); i <= _r; ++i)
#define ROF(i, r, l) for(int i = (r), _l = (l); i >= _l; --i)
#define all(v) begin(v), end(v)
#define compact(v) v.erase(unique(all(v)), end(v))
#define sz(v) (int)v.size()
#define dbg(x) "[" #x " = " << (x) << "]"
template<typename T>
bool minimize(T& a, const T& b){
if(a > b) return a = b, true; return false;
}
template<typename T>
bool maximize(T& a, const T& b){
if(a < b) return a = b, true; return false;
}
using ll = long long;
using ld = long double;
mt19937_64 rng(chrono::steady_clock::now().time_since_epoch().count());
template<typename T> T random_int(T l, T r){ return uniform_int_distribution<T>(l, r)(rng); }
template<typename T> T random_real(T l, T r){ return uniform_real_distribution<T>(l, r)(rng); }
void testcase(){
int k, n;
cin >> k >> n;
vector<pair<int, int>> opposite;
vector<int> values;
ll answer = 0;
rep(i, 0, n){
char b1, b2;
int x1, x2;
cin >> b1 >> x1 >> b2 >> x2;
if(b1 == b2) answer += abs(x1 - x2);
else {
opposite.push_back({x1, x2});
values.push_back(x1);
values.push_back(x2);
}
}
n = sz(opposite);
answer += n;
if(k == 1){
if(!values.empty()){
sort(all(values));
int median = values[sz(values) / 2];
for(int i = 0; i < n; ++i){
answer += abs(opposite[i].first - median) + abs(opposite[i].second - median);
}
}
} else{
if(!opposite.empty()){
sort(all(opposite), [&](const pair<int, int>& p1, const pair<int, int>& p2){
return p1.first + p1.second < p2.first + p2.second;
});
priority_queue<int> left;
priority_queue<int, vector<int>, greater<int>> right;
vector<ll> pref(n);
ll left_sum = 0, right_sum = 0, cur = 0;
int median = -1;
auto add = [&](int x) -> void{
left.push(x);
left_sum += x;
while(sz(left) > sz(right)){
int y = left.top();
left_sum -= y;
left.pop();
right.push(y);
right_sum += y;
}
while(!left.empty() && !right.empty() && left.top() > right.top()){
int u = left.top();
int v = right.top();
left_sum -= u;
right_sum -= v;
left.pop();
right.pop();
left.push(v);
right.push(u);
left_sum += v;
right_sum += u;
}
median = right.top();
};
for(int i = 0; i < n; ++i){
add(opposite[i].first);
add(opposite[i].second);
cur = 1ll * sz(left) * median - left_sum + right_sum - 1ll * sz(right) * median;
pref[i] = cur;
}
priority_queue<int>().swap(left);
priority_queue<int, vector<int>, greater<int>>().swap(right);
left_sum = 0;
right_sum = 0;
cur = 0;
ll extra = pref[n - 1];
for(int i = n - 1; i >= 0; --i){
add(opposite[i].first);
add(opposite[i].second);
cur = 1ll * sz(left) * median - left_sum + right_sum - 1ll * sz(right) * median;
minimize(extra, cur + (i > 0 ? pref[i - 1] : 0));
}
answer += extra;
}
}
cout << answer << '\n';
}
int main(){
ios_base::sync_with_stdio(0);
cin.tie(0);
#define filename "task"
if(fopen(filename".inp", "r")){
freopen(filename".inp", "r", stdin);
freopen(filename".out", "w", stdout);
}
int T = 1; //cin >> T;
while(T--) testcase();
return 0;
}
