Pascal :

var a,b,c:array[1..101] of longint;
    x,n,i,sum,ans:longint;

procedure qsort(l,r:longint);
var i,j,t,mid:longint;
begin
  i:=l; j:=r; mid:=a[(i+j) div 2];
  repeat
    while a[i]<mid do inc(i);
    while a[j]>mid do dec(j);
    if i<=j then
    begin
      t:=a[i]; a[i]:=a[j]; a[j]:=t;
      t:=b[i]; b[i]:=b[j]; b[j]:=t;
      t:=c[i]; c[i]:=c[j]; c[j]:=t;
      inc(i); dec(j);
    end;
  until i>j;
  if l<j then qsort(l,j);
  if i<r then qsort(i,r);
end;

begin
  
  readln(x,n);
  for i:=1 to n do
    readln(a[i],b[i],c[i]);
  qsort(1,n);
  if b[1]=x then ans:=6+abs(b[1]-c[1])*3+6
    else ans:=abs(b[1]-x)*3+6+abs(b[1]-c[1])*3+6;
  sum:=ans;
  for i:=2 to n do
  begin
    if sum<a[i] then sum:=a[i]-sum
      else sum:=0;
    if b[i]<>c[i-1] then sum:=sum+abs(b[i]-c[i-1])*3+6+abs(b[i]-c[i])*3+6
      else sum:=sum+abs(b[i]-c[i])*3+6;
    ans:=ans+sum;
  end;
  writeln(ans);
  
end.