#include <bits/extc++.h>
using namespace std;
using namespace __gnu_pbds;
inline namespace
{
template <typename T, typename Cmp = less<T>>
using OrderedSet = tree<T, null_type, Cmp, rb_tree_tag, tree_order_statistics_node_update>;
template <typename T = int>
struct PURS
{
PURS(int _n) : n(_n), tree(n + 1, 0) {}
PURS(const vector<T> &vec)
: PURS((int)vec.size())
{
for (int i = 0; i < n; i++)
add(i, vec[i]);
}
void add(int k, T x)
{
for (int p = k + 1; p <= n; p += p & -p)
tree[p] += x;
}
T sum(int l = 0) const { return sum(l, n); }
T sum(int l, int r) const { return acc(r) - acc(l); }
T get(int k) const { return sum(k, k + 1); }
void set(int k, T x) { add(k, x - get(k)); }
int size() const { return n; }
private:
int n;
vector<T> tree;
T acc(int k) const
{
T ret = 0;
for (int p = k; p; p -= p & -p)
ret += tree[p];
return ret;
}
};
} // namespace
void solve()
{
int n, k;
cin >> k >> n;
long add = 0;
vector<long> vals;
vector<array<long, 2>> u;
for (int i = 0; i < n; i++)
{
char p, q;
long s, t;
cin >> p >> s >> q >> t;
if (s < t)
swap(s, t);
if (p == q)
add += s - t;
else
{
u.push_back({s, t});
vals.push_back(s),
vals.push_back(t);
add += 1;
}
}
sort(vals.begin(), vals.end());
vals.erase(unique(vals.begin(), vals.end()), vals.end());
int z = (int)vals.size();
auto idx = [&](long x) -> int
{ return (int)(lower_bound(vals.begin(), vals.end(), x) - vals.begin()); };
int m = (int)u.size();
sort(
u.begin(), u.end(),
[&](const auto &lhs, const auto &rhs) -> bool
{ return lhs[0] + rhs[0] < lhs[1] + rhs[1]; });
vector<long> pref(m + 1), suff(m + 1);
pref[0] = suff[0] = 0;
{
PURS<long> purs(z);
OrderedSet<pair<int, int>> oset;
for (int i = 0; i < m; i++)
{
for (long x : u[i])
{
int l = idx(x);
purs.add(l, x);
oset.insert(pair(l, i));
}
int d = ((int)oset.size()) / 2, j = oset.find_by_order(d)->first;
pref[i + 1] = purs.sum(j) - purs.sum(0, j);
}
}
{
PURS<long> purs(z);
OrderedSet<pair<int, int>> oset;
for (int i = m - 1; i >= 0; i--)
{
for (int x : u[i])
{
int l = idx(x);
purs.add(l, x);
oset.insert(pair(l, i));
}
int d = ((int)oset.size()) / 2, j = oset.find_by_order(d)->first;
suff[i] = purs.sum(j) - purs.sum(0, j);
}
}
long res = LONG_MAX;
for (int i = 0; i <= m; i++)
res = min(res, pref[i] + suff[i]);
cout << res + add << '\n';
}
int main()
{
ios_base::sync_with_stdio(false), cin.tie(NULL);
solve();
return 0;
}
