#include <bits/stdc++.h>
#define forr(i, a, b) for (int i = (a); i <= (b); i++)
#define ford(i, a, b) for (int i = (a); i >= (b); i--)
#define forf(i, a, b) for (int i = (a); i < (b); i++)
#define fi first
#define se second
#define pb push_back
#define all(v) v.begin(), v.end()
#define ll long long
#define ld long double
#define pii pair<int, int>
#define pll pair<ll, ll>
#define vi vector<int>
#define vii vector<pii>
#define mask(i) (1LL << (i))
#define bit(x, i) (((x) >> (i)) & 1)
#define bp __builtin_popcountll
#define file "test"
using namespace std;
const int base = 31;
const ll mod = 1e9 + 7;
const ll oo = 1e18;
const int N = 1e6 + 5;
const int M = 1e6;
ll s[N], cnt[N];
int main()
{
ios_base::sync_with_stdio(0);
cin.tie(0);
int K, n;
cin >> K >> n;
ll res = 0;
forr(i, 1, n){
char b1, b2;
int x1, x2;
cin >> b1 >> x1 >> b2 >> x2;
if (b1 == b2){
res += abs(x1 - x2);
}
else {
res++;
cnt[x1]++;
cnt[x2]++;
}
}
forr(i, 1, M) {
s[i] = s[i - 1] + cnt[i] * i;
cnt[i] += cnt[i - 1];
}
ll cost1 = oo;
forr(x, 0, M){
cost1 = min(cost1, x * cnt[x] - s[x] + (s[M] - s[x]) - x * (cnt[M] - cnt[x]));
}
cout << res + cost1;
return 0;
}
