var
 a,p,s,d,q:array[0..16000]of longint;
 f:array[0..100,0..16000]of longint;
 n,m,i,j,k,l,r:longint;
procedure qsort(l,r:longint);
 var
  i,j,x,y: longint;
 begin
  i:=l; j:=r;
  x:=s[(l+r) div 2];
  repeat
   while s[i]<x do inc(i);
   while x<s[j] do dec(j);
   if not(i>j) then
    begin
     y:=s[i]; s[i]:=s[j]; s[j]:=y;
     y:=a[i]; a[i]:=a[j]; a[j]:=y;
     y:=p[i]; p[i]:=p[j]; p[j]:=y;
     inc(i); dec(j);
    end;
  until i>j;
  if l<j then qsort(l,j);
  if i<r then qsort(i,r);
 end;

function max(x,y:longint):longint;
 begin
  if x>y then exit(x) else exit(y);
 end;
function min(x,y:longint):longint;
 begin
  if x<y then exit(x) else exit(y);
 end;

begin
 read(n,m);
 for i:=1 to m do read(a[i],p[i],s[i]);
 qsort(1,m);
 for i:=1 to m do
  begin
   for j:=0 to s[i]-1 do f[i,j]:=f[i-1,j];
   l:=1; r:=1; d[1]:=-1; q[1]:=0;
   for j:=max(0,s[i]-a[i]) to s[i]-1 do
    begin
     k:=f[i-1,j]-p[i]*j;
     while (l<=r)and(k>=d[r]) do dec(r);
     inc(r); q[r]:=j; d[r]:=k;
    end;
   for j:=s[i] to n do
    begin
     while (l<=r)and(q[l]<j-a[i]) do inc(l);
     f[i,j]:=max(f[i-1,j],f[i,j-1]);
     if l<=r then f[i,j]:=max(f[i,j],d[l]+p[i]*j);
    end;
  end;
 writeln(f[m,n]);
end.