#include <cstdio>
#include <cstdlib>
#include <algorithm>
#include <set>
#include <utility>
#include <cstring>
#include <vector>
#include <cassert>
#define MAX ((1<<30)-1)
#define fi first
#define se second
using namespace std;
typedef pair<int, int> pii;
int K, N, lv[100005], rv[100005];
long long tot, ans;
// Segtree and set data structure that maintains median
class DS {
public:
set<pii> s1, s2;
long long st[14000005], lazy[14000005];
int lc[14000005], rc[14000005], cnt = 2;
void reset() {
memset(st, 0, sizeof(st));
memset(lazy, 0, sizeof(lazy));
memset(lc, 0, sizeof(lc));
memset(rc, 0, sizeof(rc));
s1.clear();
s2.clear();
cnt = 2;
}
void lu(int lo, int hi, int ind) {
st[ind] += (hi - lo) * lazy[ind];
if (lo + 1 < hi) {
if (lc[ind] == 0) lc[ind] = cnt++;
if (rc[ind] == 0) rc[ind] = cnt++;
lazy[lc[ind]] += lazy[ind];
lazy[rc[ind]] += lazy[ind];
}
lazy[ind] = 0;
}
long long seg_sum(int lo, int hi, int x, int ind) {
if (ind == 0) return 0;
lu(lo, hi, ind);
if (hi <= x+1) {
//printf("seg_sum(%d, %d, %d, %d): %lld\n", lo, hi, x, ind, st[ind]);
return st[ind];
}
int mid = (lo + hi) / 2;
long long res = 0;
res += seg_sum(lo, mid, x, lc[ind]);
if (mid <= x) res += seg_sum(mid, hi, x, rc[ind]);
//printf("seg_sum(%d, %d, %d, %d): %lld\n", lo, hi, x, ind, res);
return res;
}
void seg_inc(int lo, int hi, int l, int r, long long val, int ind) {
lu(lo, hi, ind);
assert(lo < r && hi > l);
if (lo >= l && hi <= r) {
lazy[ind] += val;
lu(lo, hi, ind);
return;
}
int mid = (lo + hi) / 2;
if (mid > l) {
if (lc[ind] == 0) lc[ind] = cnt++;
seg_inc(lo, mid, l, r, val, lc[ind]);
}
if (mid < r) {
if (rc[ind] == 0) rc[ind] = cnt++;
seg_inc(mid, hi, l, r, val, rc[ind]);
}
assert(lazy[ind] == 0);
lu(lo, mid, lc[ind]);
lu(mid, hi, rc[ind]);
st[ind] = st[lc[ind]] + st[rc[ind]];
}
void dump_state() {
printf("State:");
for (int i = 0; i < 10; i++) printf(" %d", seg_sum(0, MAX, i, 1));
printf("\n");
printf("Grand total: %lld\n", seg_sum(0, MAX, MAX-1, 1));
}
void ins(pii p) {
if (s2.size() == 0 || s2.begin()->fi < p.fi) s2.insert(p);
else s1.insert(p);
}
void bal() {
while (s2.size() > s1.size() + 1) {
auto it = s2.begin();
s1.insert(*it);
s2.erase(it);
}
while (s1.size() > s2.size()) {
auto it = s1.rbegin();
s2.insert(*it);
s1.erase(*it);
}
}
void add_point(int l, int r, int i) {
seg_inc(0, MAX, r+1, MAX, 2, 1);
if (l > 0) seg_inc(0, MAX, 1, l+1, -2, 1);
seg_inc(0, MAX, 0, 1, l * 2, 1);
ins({ l, 2*i });
ins({ r, 2*i+1 });
bal();
}
long long query() {
int pos = s2.begin()->fi;
return seg_sum(0, MAX, pos, 1);
}
} med;
vector<pii> sw;
long long pref[100005], suff[100005];
int main() {
scanf("%d %d", &K, &N);
for (int i = 0; i < N; i++) {
char x, y;
int v1, v2;
scanf(" %c %d %c %d", &x, &v1, &y, &v2);
lv[i] = min(v1, v2);
rv[i] = max(v1, v2);
if (x != y) {
sw.push_back({ rv[i] + lv[i], i });
tot = (tot + rv[i] - lv[i] + 1);
} else {
tot = (tot + rv[i] - lv[i]);
}
}
sort(sw.begin(), sw.end());
int M = sw.size();
for (int i = 0; i < M; i++) {
int l = lv[sw[i].se], r = rv[sw[i].se];
med.add_point(l, r, i);
pref[i+1] = med.query();
//printf("pref[%d]: %d\n", i+1, pref[i+1]);
}
med.reset();
for (int i = M-1; i >= 0; i--) {
int l = lv[sw[i].se], r = rv[sw[i].se];
med.add_point(l, r, i);
suff[i+1] = med.query();
//printf("suff[%d]: %d\n", i+1, suff[i+1]);
}
ans = 696969696969696969;
if (K == 1) {
ans = pref[M];
} else {
for (int i = 0; i <= M; i++) {
ans = min(ans, pref[i] + suff[i+1]);
}
}
printf("%lld\n", ans + tot);
return 0;
}
