BZOJ 1828

program bzoj1828;
const maxn=100001;
    check=10000000;
    
type node=record
    l,r,s,a:longint;
end;

var t:array [0..maxn*5] of node;
    a,b,c:array [0..maxn] of longint;
    n,m,i,ans,mini:longint;
    
procedure swap(var x,y:longint);
begin
  x:=x xor y;
  y:=x xor y;
  x:=x xor y;
end;

procedure qsort(l,r:longint);
var i,j,mia,mib:longint;
begin
  i:=l; j:=r;
  mia:=a[(l+r) shr 1]; mib:=b[(l+r) shr 1];
  while i<=j do
    begin
      while (b[i]<mib) or (b[i]=mib) and (a[i]<mia) do inc(i); 
      while (b[j]>mib) or (b[j]=mib) and (a[j]>mia) do dec(j); 
        if i<=j then
          begin
            swap(a[i],a[j]); 
            swap(b[i],b[j]); 
            inc(i); 
            dec(j); 
          end; 
    end; 
    if i<r then qsort(i,r); 
    if j>l then qsort(l,j); 
end; 

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

procedure build(l,r,i:longint);
var mid:longint;
begin
  t[i].l:=l;
  t[i].r:=r;
  if l=r then 
    begin
      t[i].s:=c[l];
      exit;
    end;
    mid:=(l+r)>>1; 
    build(l,mid,i<<1); 
    build(mid+1,r,i<<1+1); 
    t[i].s:=min(t[i<<1].s,t[i<<1+1].s); 
end;

procedure pass(i,add:longint); 
var lch,rch:longint; 
begin
  lch:=i shl 1; 
  rch:=lch+1; 
  inc(t[lch].s,add); 
  inc(t[rch].s,add); 
  inc(t[lch].a,add); 
  inc(t[rch].a,add); 
  t[i].a:=0; 
end; 
   
procedure change(l,r,add,i:longint); 
var mid:longint; 
begin
  if (t[i].l=l)and(t[i].r=r) then
  begin
    inc(t[i].s,add); 
    inc(t[i].a,add); 
    exit; 
  end; 
  if t[i].a<>0 then pass(i,t[i].a); 
    mid:=(t[i].l+t[i].r)>>1; 
  if r<=mid then change(l,r,add,i<<1) 
    else 
  if l>mid then change(l,r,add,i<<1+1) 
    else 
    begin
        change(l,mid,add,i<<1); 
        change(mid+1,r,add,i<<1+1); 
    end; 
    t[i].s:=min(t[i<<1].s,t[i<<1+1].s); 
end; 
   
function getans(l,r,i:longint):longint; 
var mid,ans1,ans2:longint; 
begin
  if t[i].a<>0 then pass(i,t[i].a); 
  if (t[i].l=l)and(t[i].r=r) then exit(t[i].s); 
  ans1:=check; 
  ans2:=check; 
  mid:=(t[i].l+t[i].r)>>1; 
  if r<=mid then ans1:=getans(l,r,i<<1) 
  else 
  if l>mid then ans2:=getans(l,r,i<<1+1) 
  else 
    begin
      ans1:=getans(l,mid,i<<1); 
      ans2:=getans(mid+1,r,i<<1+1); 
    end; 
  exit(min(ans1,ans2)); 
end; 
     
begin
  read(n,m); 
  for i:=1 to n do read(c[i]); 
  build(1,n,1); 
  for i:=1 to m do read(a[i],b[i]); 
  sort(1,m); 
  for i:=1 to m do
    begin
      mini:=getans(a[i],b[i],1); 
      if mini>0 then
        begin
          inc(ans); 
          change(a[i],b[i],-1,1); 
        end; 
    end; 
  writeln(ans); 
end.