// And you curse yourself for things you never done
#include<bits/stdc++.h>
#define F first
#define S second
#define PB push_back
#define sz(s) int((s).size())
#define bit(n,k) (((n)>>(k))&1)
using namespace std;
typedef long long ll;
typedef pair<int,int> pii;
const int maxn = 1e5 + 10, inf = 1e9 + 10;
const ll INF = 1e18;
ll sv[maxn];
int pt;
set<int> All;
map<int, int> L, R;
int CL, CR;
ll ANS;
void restart(){
pt = -inf;
All.clear();
ANS = 0;
L.clear(), R.clear();
CL = CR = 0;
}
ll add(int f, int s){
All.insert(f), All.insert(s);
L[f]++, R[s]++;
if(pt < f)
ANS+= f - pt;
if(s < pt)
ANS+= pt - s;
if(pt < f)
CL++;
if(s <= pt)
CR++;
while(true){
auto it = All.upper_bound(pt);
if(it == All.end())
break;
int nw = *it;
ll df = 1ll * (CR - CL) * (nw - pt);
ll num = df + ANS;
if(num < ANS){
ANS = num, pt = nw;
CR+= R[pt];
CL-= L[pt];
}
else{
break;
}
}
return ANS * 2;
}
int main(){
ios_base::sync_with_stdio(false); cin.tie(0); cout.tie();
int k, n;
cin >> k >> n;
ll sig = 0;
vector<pii> inp;
for(int i = 0; i < n; i++){
char a, b;
int l, r;
cin >> a >> l >> b >> r;
if(r < l)
swap(l, r);
sig+= r-l;
if(a != b){
sig++;
inp.PB({l, r});
}
}
sort(inp.begin(), inp.end(), [](pii a, pii b){ return a.F + a.S < b.F + b.S; } );
n = sz(inp);
if(n == 0)
return cout << sig << endl, 0;
restart();
for(int i = 0; i < n; i++){
sv[i + 1] = add(inp[i].F, inp[i].S);
}
restart();
ll ans = INF;
for(int i = n-1; i >= 0; i--){
ans = min(ans, sig + sv[i] + add(-inp[i].S, -inp[i].F));
}
if(k == 1)
ans = sig + sv[n];
return cout << ans << endl, 0;
}
