const
    MAX_R = 1010101;

var
    maxL: array[1..MAX_R] of integer;
    f: text;

begin
    Assign(f, '27-107b.txt');
    reset(f);

    var N: integer;
    readln(f, N);

    for var R := 1 to MAX_R do
        maxL[R] := 0;

    for var i := 1 to N do
    begin
        var L, R: integer;
        readln(f, L, R);
        maxL[R] := max(maxL[R], L);
    end;

    var ans := 0;
    var lastR := 0;

    for var R := 1 to MAX_R do
    begin
        if maxL[R] > lastR then
        begin
            lastR := R;
            ans += 1;
        end;
    end;

    writeln(ans);
  
end.