// Calm down.
// Think three times, code twice.
#include "bits/stdc++.h"
#define forr(_a,_b,_c) for(int _a = (_b); _a <= (_c); ++_a)
#define ford(_a,_b,_c) for(int _a = (_b) + 1; _a --> (_c);)
#define forf(_a,_b,_c) for(int _a = (_b); _a < (_c); ++_a)
#define st first
#define nd second
#define ll long long
#define ull unsigned long long
#define pii pair <int,int>
#define pll pair <ll,ll>
#define piii pair <int,pii>
#define vi vector <int>
#define pb push_back
#define mp make_pair
#define all(x) begin(x),end(x)
#define mask(i) (1LL << (i))
#define bit(x, i) (((x) >> (i)) & 1)
#define bp __builtin_popcountll
#define file "test"
using namespace std;
const int N = 1e6 + 5;
const int mod = 1e9 + 7; // 998244353
const ll oo = 1e18;
ll n, k;
void to_nho_cau() {
cin >> k >> n;
vector<ll> f;
ll ans = 0, cur = 0;
forr(i, 1, n) {
char x, y; ll a, b; cin >> x >> a >> y >> b;
if(x != y) {
ans++;
f.pb(a); f.pb(b);
} else {
ans += abs(a - b);
}
}
cur = ans;
// cout << cur << "\n";
if(f.size()) {
sort(all(f));
ll mid = f[(f.size() - 1) / 2];
forf(i, 0, f.size()) {
ans = ans + abs(mid - f[i]);
// cout << mid << " " << f[i] << "\n";
}
// cout << ans << "\n";
mid = mid + 1;
forf(i, 0, f.size()) {
cur = cur + abs(mid - f[i]);
}
}
ans = min(ans, cur);
cout << ans << "\n";
}
signed main(){
ios_base::sync_with_stdio(0);cin.tie(0);
#ifdef LOCAL
freopen(file".inp","r",stdin);
freopen(file".out","w",stdout);
#endif
int t = 1;
//cin >> t;
while(t--) to_nho_cau();
}
/*
1.self check:
2.long long
3.size of array
4.code for testing
5.initializing
6.modulo number
*/
/**
∧__∧
（｀•ω• )づ__∧
（つ /( •ω•。)
しーＪ (nnノ) pat pat
**/
/** /\_/\
* (= ._.)
* / >☕ \>💻
**/
