// 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];
vector<pii> vec;
int LST;
vector<int> arr;
void restart(){
vec.clear();
LST = -1;
}
ll calc(int pos){
ll num = 0;
for(pii p : vec){
if(pos < p.F)
num+= p.F - pos;
if(p.S < pos)
num+= pos - p.S;
}
return num;
}
ll add(int f, int s){
vec.PB({f, s});
int l = -1, r = sz(arr)-1;
while(r-l > 1){
int mid = (l + r) >> 1;
if(calc(arr[mid]) > calc(arr[mid+1]))
l = mid;
else
r = mid;
}
assert(LST <= r);
LST = r;
return calc(arr[r]) * 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);
for(int i = 0; i < n; i++){
arr.PB(inp[i].F);
arr.PB(inp[i].S);
}
sort(arr.begin(), arr.end());
arr.resize( unique(arr.begin(), arr.end()) - arr.begin() );
restart();
for(int i = 0; i < n; i++){
sv[i + 1] = add(inp[i].F, inp[i].S);
}
for(int i = 0; i < sz(arr); i++){
arr[i]*=-1;
}
reverse(arr.begin(), arr.end());
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;
}
