import java.io.*;
import java.util.*;
public class bridge {
public static void main(String[] args) {
Kattio io = new Kattio(System.in);
int K = io.getInt();
int N = io.getInt();
long same = 0;
ArrayList<Person> persons = new ArrayList<>();
int maxPos = 0;
for (int i = 0; i < N; i++) {
char P = io.getWord().charAt(0);
int S = io.getInt();
char Q = io.getWord().charAt(0);
int T = io.getInt();
if (P == Q)
same += Math.abs(S - T);
else {
persons.add(new Person(S, T));
maxPos = Math.max(Math.max(S, T), maxPos);
}
}
if (K == 1) {
int min = 0;
int max = maxPos;
while (min < max) {
int mid = (min + max) / 2;
if (value(persons, mid) < value(persons, mid+1)) {
max = mid;
} else {
min = mid+1;
}
}
io.println(same + value(persons, min));
} else if (K == 2) {
int min = 0;
int max = maxPos;
while (min < max) {
int mid = (min + max) / 2;
// io.println(min + " " + mid + " " + max + " " + value2(persons, mid));
if (value2(persons, mid) < value2(persons, mid+1)) {
max = mid;
} else {
min = mid+1;
}
}
io.println(same + value2(persons, min));
}
io.close();
}
private static long value2(ArrayList<Person> persons, int a) {
int min = 0;
int max = a-1;
while (min < max) {
int mid = (min + max) / 2;
if (value3(persons, mid, a) < value3(persons, mid+1, a)) {
max = mid;
} else {
min = mid+1;
}
}
return value3(persons, min, a);
}
private static long value3(ArrayList<Person> persons, int l, int r) {
long sum = 0;
for (Person p : persons) {
int d1 = Math.abs(p.S - l) + Math.abs(p.T - l) + 1;
int d2 = Math.abs(p.S - r) + Math.abs(p.T - r) + 1;
sum += Math.min(d1, d2);
}
return sum;
}
private static long value(ArrayList<Person> persons, int bridge) {
long sum = 0;
for (Person p : persons) {
sum += Math.abs(p.S - bridge);
sum += Math.abs(p.T - bridge);
sum++;
}
return sum;
}
static class Person {
int S, T;
Person(int s, int t) {
S = s;
T = t;
}
}
}
class Kattio extends PrintWriter {
public Kattio(InputStream i) {
super(new BufferedOutputStream(System.out));
r = new BufferedReader(new InputStreamReader(i));
}
public Kattio(InputStream i, OutputStream o) {
super(new BufferedOutputStream(o));
r = new BufferedReader(new InputStreamReader(i));
}
public boolean hasMoreTokens() {
return peekToken() != null;
}
public int getInt() {
return Integer.parseInt(nextToken());
}
public double getDouble() {
return Double.parseDouble(nextToken());
}
public long getLong() {
return Long.parseLong(nextToken());
}
public String getWord() {
return nextToken();
}
private BufferedReader r;
private String line;
private StringTokenizer st;
private String token;
private String peekToken() {
if (token == null)
try {
while (st == null || !st.hasMoreTokens()) {
line = r.readLine();
if (line == null) return null;
st = new StringTokenizer(line);
}
token = st.nextToken();
} catch (IOException e) { }
return token;
}
private String nextToken() {
String ans = peekToken();
token = null;
return ans;
}
public String getLine() {
token = null;
try {
return r.readLine();
} catch (IOException e) {}
return null;
}
}
