#include <bits/stdc++.h>
using namespace std;
#define ll long long
#define ld long double
#define pb push_back
#define all(x) begin(x), end(x)
#define SZ(x) (int)(x).size()
#define cps(x) sort(all(x)), (x).erase(unique(all(x)), end(x))
mt19937 rng(chrono::steady_clock::now().time_since_epoch().count());
const int n0 = 1e5 + 123, m0 = 4e5 + 123;
int n, k, m, l[n0], r[n0], l0[n0], r0[n0];
ll ans, pref[n0], suf[n0];
vector <int> mr[m0], ml[m0];
int M;
ll q[2][m0], val[2][m0], Q[2], VAL[2];
void upd(int c, int x, ll y) {
Q[c]++, VAL[c] += y;
for (; x < M; x |= (x + 1)) {
val[c][x] += y;
q[c][x]++;
}
}
ll getsum(int c, int x) {
ll res = 0;
for (; x >= 0; x = (x & (x + 1)) - 1)
res += val[c][x];
return res;
}
ll getnum(int c, int x) {
ll res = 0;
for (; x >= 0; x = (x & (x + 1)) - 1)
res += q[c][x];
return res;
}
void clean() {
Q[0] = Q[1] = VAL[0] = VAL[1] = 0;
for (int i = 0; i < M; i++)
val[0][i] = val[1][i] = q[0][i] = q[1][i] = 0;
}
int main() {
ios_base::sync_with_stdio(false), cin.tie(NULL);
cin >> k >> n;
for (int i = 0; i < n; i++) {
char c1, c2;
int L, R;
cin >> c1 >> L >> c2 >> R;
if (L > R) swap(L, R);
ans += R - L;
if (c1 != c2) {
l[m] = L, r[m] = R;
m++;
}
}
vector <int> v;
for (int i = 0; i < m; i++)
v.pb(l[i]), v.pb(r[i]);
sort(all(v));
if (k == 1) {
int j = SZ(v) / 2;
for (int i = 0; i < m; i++) {
if (v[j] < l[i]) ans += 2 * (l[i] - v[j]);
if (r[i] < v[j]) ans += 2 * (v[j] - r[i]);
}
} else {
v.erase(unique(all(v)), end(v));
vector <int> vec;
for (int i = 0; i < m; i++) {
l0[i] = lower_bound(all(v), l[i]) - v.begin();
r0[i] = lower_bound(all(v), r[i]) - v.begin();
vec.pb(l[i] + r[i]);
ml[l0[i]].pb(i), mr[r0[i]].pb(i);
}
cps(vec);
ll num = 0, cur = 0;
for (int i = 0; i < SZ(v); i++) {
if (i)
cur += (v[i] - v[i - 1]) * num;
pref[i] = cur;
num += SZ(mr[i]);
}
num = 0, cur = 0;
for (int i = SZ(v) - 1; i >= 0; i--) {
if (i < SZ(v) - 1)
cur += (v[i + 1] - v[i]) * num;
suf[i] = cur;
num += SZ(ml[i]);
}
ll can = 1e18;
M = SZ(vec);
vector <array <int, 2>> seg;
for (int i = 0; i < SZ(v); i++) {
//clean();
seg.clear();
for (int j = i + 1; j < SZ(v); j++) {
for (int k : mr[j]) {
int L = l[k], R = r[k];
if (L < v[i]) continue;
//int pos = lower_bound(all(vec), L + R) - vec.begin();
//upd(0, pos, L);
//upd(1, pos, R);
seg.pb({L, R});
}
//int pos2 = upper_bound(all(vec), v[i] + v[j]) - vec.begin() - 1;
//ll tmp = getsum(0, pos2) - getnum(0, pos2) * v[i];
//ll tmp2 = getnum(1, pos2) * v[j] - getsum(1, pos2);
//tmp2 = (Q[1] * v[j] - VAL[1]) - tmp2;
//can = min(can, pref[i] + suf[j] + tmp + tmp2);
ll tmp = 0;
for (auto k : seg)
tmp += 2 * min(k[0] - v[i], v[j] - k[1]);
can = min(can, pref[i] + suf[j] + tmp);
}
}
ans += can;
}
cout << ans + m;
}
