#include <bits/stdc++.h>
using namespace std;
using ll = long long;
struct Fenwick
{
int n;
std::vector<ll> f;
Fenwick(int nn = 0)
{
init(nn);
}
void init(int n_)
{
n = n_;
f.assign(n + 1, 0);
}
void update(int i, int x)
{
for (; i <= n; i += i & -i)
f[i] += x;
}
ll query(int i)
{
ll ans = 0;
for (; i > 0; i -= i & -i)
ans += f[i];
return ans;
}
int lowerbound(ll sum)
{
int pos = 0;
for (int i = 1 << 25; i > 0; i /= 2)
if (pos + i <= n && f[pos + i] < sum)
pos += i, sum -= f[pos];
return pos + 1;
}
};
int main()
{
std::cin.tie(NULL)->std::ios::sync_with_stdio(false);
int k, n;
std::cin >> k >> n;
ll extra = 0;
std::vector<std::pair<int, int>> v;
std::map<int, int> comp, decomp;
// Fenwick fenwick(100);
// std::vector<int> a = {1, 0, 1, 0, 1, 0, 1, 0, 1, 0};
// for (int i = 0; i < 10; ++i)
// {
// fenwick.update(i + 1, a[i]);
// }
// std::cout << fenwick.lowerbound(0) << std::endl;
for (int i = 0; i < n; ++i)
{
char z1, z2;
int a, b;
std::cin >> z1 >> a >> z2 >> b;
if (z1 == z2)
extra += std::abs(b - a);
else
v.push_back({a, b}), comp[a], comp[b];
}
n = v.size();
int cnt = 1;
for (auto &[x, _] : comp)
{
comp[x] = cnt;
decomp[cnt++] = x;
}
std::sort(v.begin(), v.end(), [](auto &a, auto &b)
{ return a.first + a.second < b.first + b.second; });
std::vector<ll> prefix(n + 1);
Fenwick f(2 * n), fsum(2 * n);
for (int i = 1; i <= n; ++i)
{
auto [l, r] = v[i - 1];
f.update(comp[l], 1);
f.update(comp[r], 1);
fsum.update(comp[l], l);
fsum.update(comp[r], r);
ll med = f.lowerbound(i);
ll lside = fsum.query(med);
ll rside = fsum.query(2 * n) - lside;
prefix[i] = i * (decomp[med]) - lside + rside - i * (decomp[med]);
}
ll ans = prefix[n];
if (k == 2)
{
f.init(2 * n);
fsum.init(2 * n);
for (int i = n; i > 0; --i)
{
auto [l, r] = v[i - 1];
f.update(comp[l], 1);
f.update(comp[r], 1);
fsum.update(comp[l], l);
fsum.update(comp[r], r);
ll med = f.lowerbound(n - i + 1);
ll lside = fsum.query(med);
ll rside = fsum.query(2 * n) - lside;
ans = std::min(ans, prefix[i - 1] + i * (decomp[med]) - lside + rside - i * (decomp[med]));
}
}
std::cout << n + extra + ans << '\n';
return 0;
}
