#include <cstdio>
#include <algorithm>
#include <vector>
#include <queue>
#include <cstring>
#include <cassert>
#include <cstdlib>
#include <ctime>
using namespace std;
typedef long long ll;
int N,K,n;
struct pp{
ll x,y;
bool operator<(const pp& r)const{
return x+y<r.x+r.y;
}
}a[200010];
ll lu[500010];
int sz;
ll base;
ll sum[500010],cnt[500010];
ll L[200010],R[200010];
void add(ll tree[],int x,ll c){
x++;
while(x<=sz){
tree[x]+=c;
x+=x&-x;
}
}
ll query(ll tree[],int x){
x++;
ll ret=0ll;
while(x){
ret+=tree[x];
x-=x&-x;
}
return ret;
}
void compress(){
for(int i=0;i<n;i++){
lu[sz++]=a[i].x;
lu[sz++]=a[i].y;
}
sort(lu,lu+sz);
sz=unique(lu,lu+sz)-lu;
for(int i=0;i<n;i++){
a[i].x=(lower_bound(lu,lu+sz,a[i].x)-lu)+0ll;
a[i].y=(lower_bound(lu,lu+sz,a[i].y)-lu)+0ll;
}
}
priority_queue<ll> lo;
priority_queue<ll,vector<ll>,greater<ll> > hi;
void init(){
while(!lo.empty())lo.pop();
while(!hi.empty())hi.pop();
memset(sum,0,sizeof(sum));
memset(cnt,0,sizeof(cnt));
}
void push(ll x,ll& Sum){
Sum+=lu[x];
add(sum,x,lu[x]);
add(cnt,x,1ll);
if(lo.size()==hi.size())lo.push(x);
else hi.push(x);
if(!lo.empty()&&!hi.empty()&&lo.top()>hi.top()){
ll a=lo.top(),b=hi.top();
lo.pop();hi.pop();
lo.push(b),hi.push(a);
}
}
ll getMid(){
return lo.top();
}
void f(ll d[]){
init();
ll mid,loSum,loCnt,hiSum,hiCnt,Sum=0;
for(int i=0;i<n;i++){
push(a[i].x,Sum);
push(a[i].y,Sum);
mid = getMid();
loSum = query(sum,mid);
loCnt = query(cnt,mid);
hiSum = Sum-loSum;
hiCnt = (i+1)*2ll - loCnt;
d[i] = (lu[mid]*loCnt-loSum) + (hiSum-lu[mid]*hiCnt);
}
}
int main(){
scanf("%d%d",&K,&N);
char t1,t2;
ll x,y;
for(int i=0;i<N;i++){
scanf(" %c %lld %c %lld",&t1,&x,&t2,&y);
if(t1!=t2){
a[n].x=min(x,y);
a[n++].y=max(x,y);
base++;
}else{
base+=abs(x-y);
}
}
if(n==0){
printf("%lld\n",base);
return 0;
}
compress();
sort(a,a+n);
if(K==1){
f(L);
printf("%lld\n",L[n-1]+base);
}else{
f(L);
reverse(a,a+n);
f(R);
ll ans = L[n-1];
for(int i=0;i<n-1;i++){
ans = min(ans,L[i]+R[n-2-i]);
}
printf("%lld\n",ans+base);
}
return 0;
}
