/*
* Created: 2022-07-23 16:00
*/
#ifndef LOCAL
#pragma GCC optimize("O3,unroll-loops")
#pragma GCC target("avx2,bmi,bmi2,lzcnt,popcnt")
#endif
#include <bits/stdc++.h>
using namespace std;
using ll = long long;
#define FOR(i,a,b) for(int i=int(a);i<int(b);i++)
#define rep(i,b) FOR(i,0,b)
#define FORN(i,a,b) for(int i=int(b)-1;i>=a;i--)
#define per(i,b) FORN(i,0,b)
#define mkp make_pair
#define pb push_back
#define ep emplace_back
#define ff first
#define ss second
#define bg begin()
#define ed end()
#define sz(x) (int)x.size()
#define all(x) (x).bg,(x).ed
#define FIO ios_base::sync_with_stdio(0);\
cin.tie(0);
template<class t> using vc=vector<t>;;
template<class t> using vvc=vc<vc<t>>;
using pii=pair<int,int>;
using pll=pair<ll,ll>;
using vi= vc<int>;
using vll= vc<ll>;
#ifdef LOCAL
#include "/home/fuad/cp/dbg.h"
#else
#define dbg(x...)
#endif
mt19937 rng(chrono::steady_clock::now().time_since_epoch().count());
mt19937_64 rngll(chrono::steady_clock::now().time_since_epoch().count());
void solve() {
int n, k;
cin >> k >> n;
vc<ll> v;
ll ans=0;
rep(i,n) {
char a, b;
int c, d;
cin >> a >> c >> b >> d;
if(a == b) {
ans+=abs(c-d);
}
else {
v.pb(c);
v.pb(d);
}
}
sort(all(v));
int mid = v[v.size()/2];
for(int i:v) {
ans+=abs(i-mid);
}
cout << ans +v.size()/2<< "\n";
}
int main () {
FIO;
int t=1;
// cin >> t;
while(t--)
solve();
}
