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.