#include <bits/stdc++.h>
using namespace std;
typedef long long ll;
const int MAXN = 1e5;
const int INF = 2e9;
const ll INFLL = 1e18;
int k, n;
int a[MAXN], b[MAXN];
ll ans = INFLL;
vector<int> bridges;
void solve() {
ll res = 0;
for (int i=0; i<n; i++) {
int d = INF;
for (int bridge : bridges) {
d = min(d, abs(a[i] - bridge) + 1 + abs(b[i] - bridge));
}
res += d;
}
ans = min(ans, res);
}
void rec(int toPut, int i) {
if (toPut == 0) {
solve();
return;
}
for (int j=i; j<2*n; j++) {
bridges.push_back((j < n ? a[j] : b[j-n]));
rec(toPut - 1, j+1);
bridges.pop_back();
}
}
int main() {
ios_base::sync_with_stdio(false); cin.tie(NULL);
cin >> k >> n;
ll base = 0;
for (int i=0; i<n; i++) {
char side1, side2;
cin >> side1 >> a[i] >> side2 >> b[i];
if (side1 == side2) {
base += abs(b[i] - a[i]);
n--; i--;
continue;
}
if (a[i] > b[i]) swap(a[i], b[i]);
}
k = min(k, n);
rec(k, 0);
cout << base + ans << '\n';
return 0;
}
