program ACM;
const
maxN = 400000;
var
n, i, j: longint;
a, b, f: array[0..maxN] of int64;
x: array[0..maxN] of longint;
procedure enter;
var
i: longint;
begin
readln(n);
for i := 1 to 2*n do readln(a[i], b[i]);
end;
procedure sort(l, r: longint);
var
i, j: longint;
x, y, z: int64;
begin
i := l; j := r;
x := a[(l + r) div 2] - b[(l + r) div 2];
repeat
while a[i] - b[i] < x do inc(i);
while x < a[j] - b[j] do dec(j);
if i <= j then
begin
y := a[i]; a[i] := a[j]; a[j] := y;
y := b[i]; b[i] := b[j]; b[j] := y;
z := x[i]; x[i] := x[j]; x[j] := z;
inc(i); dec(j);
end;
until i > j;
if l < j then sort(l, j);
if i < r then sort(i, r);
end;
procedure solve;
var
i, j: longint;
begin
sort(1, 2*n);
for i := 1 to 2*n do
begin
f[i] := f[i-1] + a[i];
x[i] := x[i-1] + 1;
if (x[i-1] < n) and (f[i] > f[i-1] + b[i]) then
begin
f[i] := f[i-1] + b[i];
x[i] := x[i-1];
end;
end;
writeln(f[2*n]);
end;
begin
assign(input, 'ACM.INP'); reset(input);
assign(output, 'ACM.OUT'); rewrite(output);
enter;
solve;
close(input); close(output);
end.