#include <bits/stdc++.h>
using namespace std;
#define int int64_t
#define pii array<int,2>
struct cmp {
bool operator()(const pii &x, const pii &y) {
return (x[0] + x[1]) < (y[0] + y[1]);
}
};
signed main() {
int k, n;cin>>k>>n;
vector<pii> dif;
int dis = 0;
for (int i=0;i<n;i++) {
char c1,c2;
int p1,p2;
cin>>c1>>p1>>c2>>p2;
if (c1 == c2) {
dis += abs(p1-p2);
}
else {
dif.push_back({p1,p2});
}
}
if (dif.size() == 0) {
cout<<dis<<"\n";
return 0;
}
if (k == 1 || dif.size() == 1) {
vector<int> al;
for (auto x:dif) {
al.push_back(x[0]);
al.push_back(x[1]);
}
sort(al.begin(),al.end());
int med = al[al.size() / 2];
for (int x:al) {
dis += abs(x - med);
}
dis += dif.size();
cout<<dis<<"\n";
return 0;
}
sort(dif.begin(),dif.end(), cmp());
multiset<int> m1, m2;
int s1 = 0, s2 = 0;
function<void(int,int)> insert=[&](int num1, int num2) {
m1.insert(num1);
m1.insert(num2);
s1 += num1;
s1 += num2;
int num = *m1.rbegin();
s1 -= num;
s2 += num;
m1.erase(m1.find(num));
m2.insert(num);
while (*m2.begin() < *m1.rbegin()) {
int f = *m2.begin(),s=*m1.rbegin();
m2.erase(m2.find(f));
m1.erase(m1.find(s));
m1.insert(f);
m2.insert(s);
s2 -= f;s1 += f;
s2 += s;s1 -= s;
}
};
vector<int> cst1, cst2;
vector<int> al;
if (dif.size() > 4000) {
for (auto x:dif) {
insert(x[0], x[1]);
assert(m1.size() == m2.size());
cst1.push_back(s2 - s1);
}
}
else {
for (auto x:dif) {
al.push_back(x[0]);
al.push_back(x[1]);
sort(al.begin(),al.end());
int med = al[al.size()/2];
int tmp=0;
for (int y:al) {
tmp += abs(y-med);
}
cst1.push_back(tmp);
}
}
reverse(dif.begin(),dif.end());
m1.clear();m2.clear();
s1=s2=0;
al.clear();
if (dif.size() > 4000) {
for (auto x:dif) {
insert(x[0], x[1]);
assert(m1.size() == m2.size());
cst2.push_back(s2 - s1);
}
}
else {
for (auto x:dif) {
al.push_back(x[0]);
al.push_back(x[1]);
sort(al.begin(),al.end());
int med = al[al.size()/2];
int tmp=0;
for (int y:al) {
tmp += abs(y-med);
}
cst2.push_back(tmp);
}
}
reverse(cst2.begin(),cst2.end());
int res = 1e18;
for (int i=1;i<(int)cst1.size();i++) {
res = min(res, cst1[i-1] + cst2[i]);
}
res += (int)dif.size();
cout<<res+dis<<"\n";
}
