// Alir3za.Zar3 -> Shiraz , Iran
#include <bits/stdc++.h>
using namespace std;
#define int long long
const int N = 1e5+7 , Inf = 2e18;
int k,n , out=0 , O = 1e9;
vector<pair<int,int>> q;
void iN ()
{
cin >> k >> n;
for (int i=1; i<=n; i++)
{
char P , Q; int S , T;
cin >> P >> S >> Q >> T;
out += abs(S - T) + (P != Q);
if (P != Q)
q.push_back({min(S,T),max(S,T)});
}
}
pair<int,bool> oK (int v1 , int v2)
{
int s = 0 , l=0 , r=0;
for (auto [a,b] : q)
{
int k1 = 0 , k2 = 0;
if (a > v2) r++;
if (v1 <= a and b <= v2)
k1=a-v1 , k2=v2-b;
else if (a <= v1 and v2 <= b)
k1=0 , k2=0;
else if (a <= v1 and v1 <= b)
k1=0 , k2=v2-b;
else if (a <= v2 and v2 <= b)
k1=v1-a , k2=0;
else if (b < v1)
k1=v1-b , k2=v2-b;
else if (a > v2)
k1=a-v1 , k2=a-v2;
k1 <<= 1; k2 <<= 1;
s += min(k1 , k2);
if (k2 < k1 and b <= v2) l++;
}
return {s , r>=l};
}
int nxt_Binary (int l , int r , int p)
{
while (r-l > 2)
{
int o = (l+r) >> 1;
if (oK(p , o).second) l=o;
else r=o;
}
int mn = Inf;
for (int i=l; i<=r; i++)
mn = min(mn , oK(p , i).first);
return mn;
}
void Ternary_Search ()
{
int l=0 , r=O;
while (r-l > 2)
{
int o = (r-l) / 3;
int v1 = l+o , v2 = l+2*o;
int q1 = nxt_Binary(v1,O,v1);
int q2 = nxt_Binary(v2,O,v2);
if (q1 < q2) r=v2;
else if (q1 == q2) l=v1,r=v2;
else l=v1;
}
int mn = Inf;
for (int i=l; i<=r; i++)
mn = min(mn , nxt_Binary(i,O,i));
out += mn;
}
void ouT ()
{
cout << out << '\n';
}
signed main()
{
ios::sync_with_stdio(false);
cin.tie(0); cout.tie(0);
iN();
ouT();
}
