#include <iostream>
#include <vector>
#include <algorithm>
#include <set>
#include <assert.h>
using namespace std;
typedef long long ll;
#define all(x) begin(x), end(x)
#define sz(x) (int) x.size()
const int PRIME = 1e9 + 7;
bool locationCmp(pair<int, int>& a, pair<int, int>& b){
return a.first + a.second < b.first + b.second;
}
template<class T>
vector<int> calcDist(T start, T end, int size){
vector<int> out(size);
int ind = 0;
multiset<int> smaller, bigger;
smaller.insert(start->first); bigger.insert(start->second);
int smallSum, bigSum;
smallSum = start->first; bigSum = start->second;
out[ind] = bigSum - smallSum;
start++;
while(start != end){
smaller.insert(start->first);
bigger.insert(start->second);
smallSum += start->first;
bigSum += start->second;
while(*smaller.rbegin() > *bigger.begin()){
int sumChange = *bigger.begin() - *smaller.rbegin();
smallSum += sumChange;
bigSum -= sumChange;
bigger.insert(*smaller.rbegin());
smaller.insert(*bigger.begin());
bigger.erase(bigger.begin());
smaller.erase(--smaller.end());
}
ind++;
start++;
out[ind] = bigSum - smallSum;
}
return out;
}
int main(){
ios_base::sync_with_stdio(0); cin.tie(0);
int k, n;
cin >> k >> n;
vector<pair<int, int>> paths;
int sameSideAns = 0;
for(int i = 0; i < n; i++){
char side1, side2;
int loc1, loc2;
cin >> side1 >> loc1 >> side2 >> loc2;
if(side1 == side2){
sameSideAns += abs(loc1 - loc2);
continue;
}
if(loc1 > loc2){
swap(loc1, loc2);
}
// idk if this works
assert(loc1 <= loc2);
paths.push_back({loc1, loc2});
}
sort(all(paths), locationCmp);
vector<int> fromLeft = calcDist(paths.begin(), paths.end(), sz(paths));
if(k == 1){
cout << sameSideAns + fromLeft[sz(paths)-1] + sz(paths) << '\n';
return 0;
}
vector<int> fromRight = calcDist(paths.rbegin(), paths.rend(), sz(paths));
int bridgeAns = INT32_MAX;
for(int i = 0; i < sz(paths) - 1; i++){
bridgeAns = min(bridgeAns, fromLeft[i] + fromRight[sz(paths) - i - 2]);
}
// for(int el: fromLeft){
// cout << el << ' ';
// }
// cout << '\n';
// for(int el: fromRight){
// cout << el << ' ';
// }
// cout << '\n';
cout << sameSideAns + bridgeAns + sz(paths) << '\n';
}
