#include <bits/stdc++.h>
#define F first
#define S second
#define all(x) x.begin(), x.end()
#define pb push_back
#define FIO ios_base::sync_with_stdio(false); cin.tie(0); cout.tie(0)
using namespace std;
typedef long long ll;
typedef pair <ll, ll> pii;
const int N = 1e5 + 7;
int n, k;
int l[N], r[N], l_[N], r_[N], ind[N];
int main () {
FIO;
cin >> k >> n;
ll res = 0;
int cnt = 0;
for (int i = 0; i < n; i++) {
int a, b;
char c1, c2;
cin >> c1 >> a >> c2 >> b;
if (c1 == c2) res += abs(a-b);
else {
res++;
l_[cnt] = min(a, b);
r_[cnt++] = max(a, b);
}
}
for (int i = 0; i < cnt; i++) ind[i] = i;
sort(ind, ind+cnt, [&](int x, int y) {return l_[x]+r_[x] < l_[y]+r_[y];});
for (int i = 0; i < cnt; i++) l[i] = l_[ind[i]], r[i] = r_[ind[i]];
if (k == 1) {
multiset <int> s;
ll d = -2*cnt, h = 0;
for (int i = 0; i < cnt; i++) {
s.insert(l[i]);
s.insert(r[i]);
h += l[i]+r[i];
}
for (int i = 0; i < cnt; i++) s.erase(--s.end());
int la = 0;
for (auto x : s) {
h += d*(x-la);
la = x;
d += 2;
}
res += h;
}
else {
set <pii> s;
map <ll, ll> ma;
ll y = -1, z = 0, h = 0;
auto add = [&](ll x) {
s.insert({x, ma[x]++});
s.insert({x, ma[x]++});
if (y == -1) {y = s.begin() -> F; return;}
h += abs(y-x);
auto p = s.find({y, z});
if (x >= y) ++p;
else --p;
pii ny = *p;
h -= max(0LL, ny.F-y);
y = ny.F;
z = ny.S;
};
vector <ll> pre(cnt+1, 0);
for (int i = 0; i < cnt; i++) {
add(l[i]);
add(r[i]);
pre[i+1] = h;
}
s.clear();
ma.clear();
y = -1; z = 0; h = 0;
ll mn = pre[cnt];
for (int i = cnt-1; i >= 0; i--) {
add(l[i]);
add(r[i]);
mn = min(mn, pre[i]+h);
}
res += mn;
}
cout << res << "\n";
return 0;
}
