#include <bits/stdc++.h>
#define int long long
// #pragma GCC target("avx2,bmi,bmi2,lzcnt,popcnt")
// #pragma GCC optimize("O3")
// #pragma GCC optimize("unroll-loops")
#define F first
#define S second
#define mp make_pair
#define pb push_back
#define all(x) x.begin(), x.end()
#define kill(x) cout << x << "\n", exit(0);
#define pii pair<int, int>
#define pll pair<long long, long long>
#define endl "\n"
using namespace std;
typedef long long ll;
// typedef __int128_t lll;
typedef long double ld;
const int MAXN = (int)1e6 + 7;
const int MOD = 998244353;
const ll INF = (ll)1e18 + 7;
int n, m, k, tmp, t, tmp2, tmp3, tmp4, u, v, w, flag, q, ans, N, res, pre_ans;
char ch, ch2;
vector<int> vec[2][MAXN], cmp;
vector<pair<int, pii>> ord;
int ps[2][MAXN];
/* Median DS */
priority_queue<int> lpq;
priority_queue<int, vector<int>, greater<int>> rpq;
int lsum, rsum;
inline void add(int x) {
int median = (lpq.size()? lpq.top() : INF);
if (x <= median) lpq.push(x), lsum += x;
else rpq.push(x), rsum += x;
if (lpq.size() < rpq.size()) {
rsum -= rpq.top(); lsum += rpq.top();
lpq.push(rpq.top()); rpq.pop();
} else if (rpq.size()+1 < lpq.size()) {
lsum -= lpq.top(); rsum += lpq.top();
rpq.push(lpq.top()); lpq.pop();
}
}
/* Median DS */
int32_t main() {
#ifdef LOCAL
freopen("inp.in", "r", stdin);
freopen("res.out", "w", stdout);
#else
ios::sync_with_stdio(0); cin.tie(0); cout.tie(0);
#endif
cin >> k >> n;
for (int i=1; i<=n; i++) {
cin >> ch >> u >> ch2 >> v;
if (ch == ch2) pre_ans += abs(u-v);
else ord.pb({u+v, {u, v}});
}
N = ord.size(); sort(all(ord)); pre_ans += N;
lsum = rsum = 0;
for (int i=1; i<=N; i++) {
add(ord[i-1].S.F); add(ord[i-1].S.S);
ps[0][i] = rsum - lsum;
}
ans = ps[0][N];
if (k == 1) kill(ans+pre_ans);
lsum = rsum = 0;
while (lpq.size()) lpq.pop();
while (rpq.size()) rpq.pop();
for (int i=N; i>=1; i--) {
add(ord[i-1].S.F); add(ord[i-1].S.S);
ans = min(ans, rsum - lsum + ps[0][i-1]);
}
cout << pre_ans+ans << endl;
return 0;
}
