var a,b,c,d:array[1..10000]of longint;
n,i,j,sum,min,p:longint;
procedure sort(l,r:longint);
var i,j,x,t:longint;
begin
i:=l;j:=r;
x:=a[(l+r) div 2];
repeat
while a[i]<x do inc(i);
while a[j]>x 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;
inc(i);
dec(j);
end;
until i>j;
if l<j then sort(l,j);
if i<r then sort(i,r);
end;
begin
readln(n);
for i:=1 to n do
readln(a[i],b[i]);
sort(1,n);
sum:=0;
fillchar(c,sizeof(c),0);
for i:=1 to n do
begin
if sum=0 then
begin
c[1]:=b[1];
inc(sum);
end
else
begin
min:=maxlongint;
p:=0;
for j:=1 to sum do
if(b[i]<c[j])and(min>c[j]-b[i])then
begin
p:=j;
min:=c[j]-b[i];
end
else if (a[i]>c[j]) then p:=j;
if p=0 then
begin
inc(sum);
c[sum]:=b[i];
end
else
begin
c[p]:=b[i];
end;
end;
end;
write(sum)
end.