#include<bits/stdc++.h>
#define god dimasi5eks
#pragma GCC optimize("O3")
#define fi first
#define se second
#define pb push_back
#define pf push_front
using namespace std;
typedef long long ll;
const int mod = 1000000007;
const double dancila = 3.14159265359; // PI
const double eps = 1e-9;
bool cmp(pair<int, int> a, pair<int, int> b)
{
return a.fi + a.se < b.fi + b.se;
}
priority_queue<int> lpq;
priority_queue<int, vector<int>, greater<int>> rpq;
ll lsum, rsum, ansa;
ll ps[100001];
void add(int x)
{
int median = (lpq.size() ? lpq.top() : 1000000001);
if(x <= median)
{
lpq.push(x);
lsum += x;
}
else
{
rpq.push(x);
rsum += x;
}
if(rpq.size() + 1 < lpq.size())
{
int nxt = lpq.top();
lpq.pop();
rpq.push(nxt);
lsum -= nxt;
rsum += nxt;
}
else
if(lpq.size() < rpq.size())
{
int nxt = rpq.top();
rpq.pop();
lpq.push(nxt);
rsum -= nxt;
lsum += nxt;
}
}
int main()
{
ios_base::sync_with_stdio(false);
cin.tie(NULL);
int k, n;
vector<pair<int, int>> v = {{0, 0}};
cin >> k >> n;
for(int i = 0; i < n; ++i)
{
char a, b;
int x, y;
cin >> a >> x >> b >> y;
if(a == b)
ansa += abs(x - y);
else
v.push_back({x, y});
}
sort(v.begin(), v.end(), cmp);
n = v.size() - 1;
ansa += n;
lsum = rsum = 0;
for(int i = 1; i <= n; ++i)
{
add(v[i].fi);
add(v[i].se);
ps[i] = rsum - lsum;
}
ll ansb = ps[n];
if(k == 2)
{
while(lpq.size())
lpq.pop();
while(rpq.size())
rpq.pop();
lsum = rsum = 0;
for(int i = n; i >= 1; i--)
{
add(v[i].fi);
add(v[i].se);
ansb = min(ansb, rsum - lsum + ps[i - 1]);
}
}
cout << ansa + ansb;
return 0;
}
