b = (function (vb) {
                                var wb = l(tb.acc);
                                var xb = tb.unfold(wb);
                                if ((xb.Tag == 1.000000)) {
                                    var yb = s(xb).Items[0.000000];
                                    var zb = s(xb).Items[1.000000];
                                    tb.acc = { Tag: 1.000000, Value: zb };
                                    tb.current = yb;
                                    return true;
          