#include<bits/stdc++.h>
using namespace std;
#define pb push_back
#define F first
#define S second
#define debug(x) cerr<<#x<<" :"<<x<<"\n"
#define all(x) x.begin(),x.end()
#define pii pair<int,int>
#define FAST ios_base::sync_with_stdio(false), cin.tie(), cout.tie();
#define int long long
typedef long long ll;
typedef long double ld;
const int maxn = 1e5 + 7;
const int mod = 1e9 + 7;
const int INF = 1e9 + 1;
const int mlog = 20;
const int SQ = 400;
int ls, rs;
priority_queue<int> lpq;
priority_queue<int, vector<int>, greater<int>> rpq;
int pref[maxn];
bool cmp(pii a, pii b) { return a.first + a.second < b.first + b.second; }
void add(int x)
{
int median = (lpq.size() ? lpq.top() : +INF);
if (x <= median)
{
lpq.push(x);
ls += x;
} else {
rpq.push(x);
rs += x;
}
if (rpq.size() + 1 < lpq.size())
{
int nxt = lpq.top();
lpq.pop(); rpq.push(nxt);
ls -= nxt; rs += nxt;
} else if (lpq.size() < rpq.size())
{
int nxt = rpq.top();
rpq.pop();
lpq.push(nxt);
rs -= nxt; ls += nxt;
}
}
int32_t main()
{
FAST;
int n, k;
cin >> k >> n;
int ham = 0;
vector<pii> vec = {{0, 0}};
for(int i = 0; i < n; i++)
{
char a, b; int x, y;
cin >> a >> x >> b >> y;
if(a == b) ham += abs(x - y);
else vec.pb({x, y});
}
sort(all(vec), cmp);
n = vec.size() - 1;
ham += n;
ls = rs = 0;
for(int i = 1; i <= n; i++)
{
add(vec[i].F); add(vec[i].S);
pref[i] = rs - ls;
}
int ans = pref[n];
if(k == 2)
{
while(lpq.size()) lpq.pop();
while(rpq.size()) rpq.pop();
ls = rs = 0;
for(int i = n; i; i--)
{
add(vec[i].F); add(vec[i].S);
ans = min(ans, rs - ls + pref[i - 1]);
}
}
cout << ham + ans << "\n";
return 0;
}
