#include <iostream>
#include <fstream>
#include <algorithm>
#include <climits>
#include <queue>
using namespace std;
const int nmax=100005;
pair<int,int> v[nmax],a[2*nmax];
long long act,ans,fx;
int norm[nmax];
long long neinc[2*nmax],term[2*nmax],sum_neinc[2*nmax],sum_term[2*nmax];
char wh1,wh2;
int n,i,j,k,p1,p2,cate;
struct aibul_smecher
{
long long aib[nmax];
inline int lbit(int x)
{
return ((x^(x-1))&x);
}
void update(int poz,long long val)
{
for(int idx=poz;idx<=n;idx+=lbit(idx))
aib[idx]+=val;
}
long long compute(int poz)
{
long long ret=0;
for(int idx=poz;idx>0;idx-=lbit(idx))
ret+=aib[idx];
return ret; //:*
}
void clr()
{
for(int idx=1;idx<=n;idx++)
aib[idx]=0;
}
}suma,sumb,nr;
long long abss(long long x)
{
if(x<0) return -x;
return x;
}
int cb(int val)
{
int ret=0;
for(int p=17;p>=0;p--)
if(ret+(1<<p)<=cate&&norm[ret+(1<<p)]<=val)
ret+=(1<<p);
return ret;
}
void solve_1()
{
for(i=1;i<=cate;i++)
{
a[2*i-1]={v[i].first,-1};
a[2*i]={v[i].second,v[i].first};
sum_neinc[0]+=1LL*v[i].first;
}
neinc[0]=cate;
sort(a+1,a+2*cate+1);ans=LLONG_MAX;
if(!cate) ans=0;
for(i=1;i<=2*cate;i++)
{
neinc[i]=neinc[i-1],sum_neinc[i]=sum_neinc[i-1];
term[i]=term[i-1],sum_term[i]=sum_term[i-1];
if(a[i].second==-1)
neinc[i]--,sum_neinc[i]-=1LL*a[i].first;
else term[i]++,sum_term[i]+=1LL*a[i].first;
act=a[i].first;
ans=min(ans,2LL*(sum_neinc[i]-neinc[i]*act+term[i]*act-sum_term[i]));
}
}
void ins(long long a,long long b,long long val)
{
int poz=cb(val);
nr.update(poz,1);
suma.update(poz,a);
sumb.update(poz,b);
}
void del(long long a,long long b,long long val)
{
int poz=cb(val);
nr.update(poz,-1);
suma.update(poz,-a);
sumb.update(poz,-b);
}
long long qr(long long S,long long D)
{
long long sum0,sum1,nr0,nr1;
int poz=cb(S+D);
nr0=nr.compute(poz);nr1=nr.compute(n)-nr0;
sum0=1LL*suma.compute(poz);sum1=1LL*sumb.compute(n)-sumb.compute(poz);
return (1LL*sum0-1LL*nr0*S+1LL*nr1*D-1LL*sum1);
}
void solve_2()
{
long long S,D;
for(i=1;i<=2*cate;i++)
{
for(j=i;j<=2*cate;j++)
{
if(a[j].second>=a[i].first)
{
ins(a[j].second,a[j].first,a[j].second+a[j].first);
}
S=a[i].first;D=a[j].first;
ans=min(ans,2LL*(sum_neinc[j]-neinc[j]*D+term[i]*S-sum_term[i]+qr(S,D)));
}
nr.clr();
suma.clr();
sumb.clr();
//dam clear la structura
}
}
priority_queue< pair<int,int> >pq;
void solve_2_mare()
{
i=1;long long prc,cost,S,D;
int poz;
for(j=1; j<=2*cate; j++)
{
if(a[j].second>=a[i].first)
{
ins(a[j].second,a[j].first,a[j].second+a[j].first);
pq.push({-a[j].second,j});
}
prc=0;cost=1;
while(cost>prc&&i<j)
{
S=a[i].first;
D=a[j].first;
while((!pq.empty())&&-pq.top().first<a[i].first)
{
poz=pq.top().second;
del(a[poz].second,a[poz].first,a[poz].second+a[poz].first);
pq.pop();
}
ans=min(ans,2LL*(sum_neinc[j]-neinc[j]*D+term[i]*S-sum_term[i]+qr(S,D)));
prc=cost;cost=2LL*(sum_neinc[j]-neinc[j]*D+term[i]*S-sum_term[i]+qr(S,D));
i++;
}
}
}
int main()
{
//freopen("data.in","r",stdin);
ios_base::sync_with_stdio(false);
cin>>k>>n;
for(i=1;i<=n;i++)
{
cin>>wh1>>p1>>wh2>>p2;
fx+=(1LL*abss(p2-p1));
if(wh1!=wh2)
{
fx++;
if(p1>p2) swap(p1,p2);
v[++cate]={p1,p2};
}
}
for(i=1;i<=cate;i++)
norm[i]=v[i].first+v[i].second;
sort(norm+1,norm+cate+1);
solve_1();
if(k==2)
{
if(n<=1000)solve_2();
else solve_2_mare();
}
cout<<fx+ans;
return 0;
}
