#include <cstdio>
#include <cassert>
#include <algorithm>
#include <vector>
struct item {
long long sum;
int amt;
item() {
sum = amt = 0;
}
void operator+=(int k) {
sum += k;
++amt;
}
void operator-=(int k) {
sum -= k;
--amt;
}
long long calc(int x) {
return sum - (long long)x * amt;
}
};
const int N = 400000;
int n, task;
std::vector<std::pair<int, int> > pt, a, md;
item il, ir, jl, jr;
bool u[N], i_vis[N], j_vis[N];
void move_k(int &k, int cur, int jval)
{
while (k < n && md[k].first <= cur + jval) {
if (u[md[k].second]) {
jl -= a[md[k].second].second - 1;
ir += a[md[k].second].first;
}
++k;
}
}
void move_j(int &j, int &k, int cur, int &jval)
{
while (j < n << 1 && jl.amt - jr.amt <= 0) {
jval = pt[j].first;
do {
if (!j_vis[pt[j].second]) {
jr -= jval;
j_vis[pt[j].second] = true;
}
else if (a[pt[j].second].first > cur) {
u[pt[j].second] = true;
jl += jval;
}
++j;
} while (j < n << 1 && pt[j].first == jval);
move_k(k, cur, jval);
}
}
long long eval(int cur, int jval)
{
return ir.calc(cur) - il.calc(cur) + jr.calc(jval) - jl.calc(jval);
}
int main()
{
scanf("%d%d", &task, &n);
long long ans_add = 0;
for (int i = 0; i < n; ++i) {
char type1, type2;
int l, r;
scanf(" %c%d %c%d", &type1, &l, &type2, &r);
if (l > r) std::swap(l, r);
ans_add += r - l;
if (type1 != type2) {
++ans_add;
pt.push_back(std::make_pair(l, (int)a.size()));
pt.push_back(std::make_pair(r, (int)a.size()));
md.push_back(std::make_pair(l + r, (int)a.size()));
a.push_back(std::make_pair(l, r + 1));
}
}
std::sort(pt.begin(), pt.end());
std::sort(md.begin(), md.end());
n = (int)a.size();
for (int i = 0; i < n; ++i) jr += a[i].first;
int cur = 1 << 31, jval = 1 << 31, j = 0, k = 0;
move_j(j, k, cur, jval);
long long ans = eval(cur, jval);
if (task == 1) {
printf("%lld\n", ans * 2 + ans_add);
return 0;
}
for (int i = 0; i < n << 1;) {
cur = pt[i].first;
move_k(k, cur, jval);
do {
if (!i_vis[pt[i].second]) {
if (u[pt[i].second]) {
u[pt[i].second] = false;
ir -= pt[i].first;
}
i_vis[pt[i].second] = true;
}
else il += cur;
++i;
} while (i < n << 1 && pt[i].first == cur);
move_j(j, k, cur, jval);
ans = std::min(ans, eval(cur, jval));
}
for (int i = 0; i < n; ++i) il -= a[i].second - 1;
assert(!il.sum && !il.amt && !jl.sum && !jl.amt && !ir.sum && !ir.amt && !jr.sum && !jr.amt);
printf("%lld\n", ans * 2 + ans_add);
return 0;
}
