MAUAO PASCAL

var n,i: longint;
    a,b:array[0..1000000] of longint;
procedure nhap;
begin
    read(n);
    for i:=1 to n do
        read(a[i],b[i]);
end;
procedure giai;
var d,i,j:longint;
begin
    d:=0;
    for i:=1 to n do
        for j:=1 to n do
            if (i<>j) and (a[i]=b[j]) then
                inc(d);
    write(d);
end;
begin
    assign(input,'mauao.inp'); reset(input);
    assign(output,'mauao.out'); rewrite(output);
    nhap;
    giai;
end.