#include <bits/stdc++.h>
#define ll long long
#define fi first
#define se second
#define endl '\n'
#define MASK(i) (1LL << (i))
#define ull unsigned long long
#define ld long double
#define pb push_back
#define all(x) (x).begin() , (x).end()
#define BIT(x , i) ((x >> (i)) & 1)
#define TASK "task"
#define sz(s) (int) (s).size()
using namespace std;
const int mxN = 3e5 + 227;
const int inf = 1e9 + 277;
const int mod = 1e9 + 7;
const ll infll = 1e18 + 7;
const int base = 307;
const int LOG = 20;
template <typename T1, typename T2> bool minimize(T1 &a, T2 b) {
if (a > b) {a = b; return true;} return false;
}
template <typename T1, typename T2> bool maximize(T1 &a, T2 b) {
if (a < b) {a = b; return true;} return false;
}
struct item{
int b1 , z1 , b2 , z2;
} a[mxN];
vector<int> co;
struct fenwicktree{
vector<pair<ll , ll>> bit;
int n;
fenwicktree(){}
fenwicktree(int _n)
{
n = _n;
bit.resize(n + 7 , {0 , 0});
}
void update(int pos , int val)
{
int x = co[pos - 1];
if(val < 0) x = -x;
for(; pos <= n ; pos += (pos & (-pos))) {
bit[pos].fi += val;
bit[pos].se += x;
}
}
int sum(int pos)
{
int res = 0;
for(; pos > 0 ; pos -= (pos & (-pos))) res += bit[pos].fi;
return res;
}
ll sumval(int pos)
{
ll res = 0;
for(; pos > 0 ; pos -= (pos & (-pos))) res += bit[pos].se;
return res;
}
ll median()
{
if(n == 0) return 0;
int lo = 0 , hi = n;
int le = sum(n);
while(lo + 1 < hi) {
int mid = (lo + hi) / 2;
if(sum(mid) >= (le + 1) / 2) hi = mid;
else lo = mid;
}
ll ans = 0;
ans += 1LL * co[hi - 1] * sum(hi) - sumval(hi);
ans += sumval(n) - sumval(hi) - 1LL * (sum(n) - sum(hi)) * co[hi - 1];
return ans;
}
} ft1 , ft2;
int n , k;
pair<int , int> val[mxN];
int cnt[mxN];
int compress(int x)
{
return lower_bound(all(co) , x) - co.begin() + 1;
}
ll res1 = infll , res2 = infll;
ll ans1[mxN] , ans2[mxN];
void modify(int x , int y)
{
ft1.update(x , 1);
ft1.update(y , 1);
ft2.update(x , -1);
ft2.update(y , -1);
res1 = ft1.median();
res2 = ft2.median();
}
bool cmp(pair<int , int> &a , pair<int , int> &b)
{
return co[a.fi - 1] + co[a.se - 1] < co[b.fi - 1] + co[b.se - 1];
}
int CNT[mxN];
void solve()
{
cin >> k >> n;
for(int i = 1 ; i <= n ; i++) {
char c1 , c2;
cin >> c1 >> a[i].b1 >> c2 >> a[i].b2;
a[i].z1 = (c1 == 'A' ? 1 : 2);
a[i].z2 = (c2 == 'A' ? 1 : 2);
}
for(int i = 1 ; i <= n ; i++) {
if(a[i].z1 == a[i].z2) continue;
co.pb(a[i].b1);
co.pb(a[i].b2);
}
sort(all(co));
co.erase(unique(all(co)) , co.end());
for(int i = 1 ; i <= n ; i++) {
if(a[i].z1 == a[i].z2) continue;
a[i].b1 = compress(a[i].b1);
a[i].b2 = compress(a[i].b2);
}
ll re = 0;
int cnt = 0;
for(int i = 1 ; i <= n ; i++) {
if(a[i].z1 == a[i].z2) {
re += abs(a[i].b1 - a[i].b2);
continue;
}
val[++cnt] = {a[i].b1 , a[i].b2};
}
sort(val + 1 , val + 1 + cnt , cmp);
ft1 = fenwicktree(cnt * 2);
ft2 = fenwicktree(cnt * 2);
for(int i = 1 ; i <= n ; i++) {
if(a[i].z1 == a[i].z2) continue;
ft2.update(a[i].b1 , 1);
ft2.update(a[i].b2 , 1);
}
res1 = ft1.median();
res2 = ft2.median();
ans2[0] = res2;
if(k == 1) {
cout << res2 + re + cnt;
}
for(int i = 1 ; i <= cnt ; i++) {
pair<int , int> it = val[i];
modify(it.fi , it.se);
ans1[i] = res1;
ans2[i] = res2;
}
if(k == 2) {
ll ans = ans2[0];
for(int i = 1 ; i <= cnt ; i++) {
if(minimize(ans , ans1[i] + ans2[i]) == true) {
}
}
cout << ans + re + cnt << endl;
}
}
int main()
{
ios_base::sync_with_stdio(false);
cin.tie(0);
//freopen(TASK".inp" , "r" , stdin);
//freopen(TASK".out" , "w" , stdout);
int tc = 1;
//cin >> tc;
while(tc--) {
solve();
}
return 0;
}
