+{
+ unsigned result = 0;
+ symbol x("x");
+
+ epvector v1;
+ v1.push_back(expair(1, 1));
+ v1.push_back(expair(2*x, -1));
+ ex e1 = add(v1); // Should be e==1-2*x,
+ if (!e1.is_equal(1-2*x)) {
+ clog << "Failure constructing " << e1 << " from add.\n";
+ ++result;
+ }
+
+ epvector v2;
+ v2.push_back(expair(x, 1));
+ v2.push_back(expair(1,-1));
+ ex e2 = mul(v2); // Should be e==x;
+ if (!e2.is_equal(x)) {
+ clog << "Failure constructing " << e2 << " from mul.\n";
+ ++result;
+ }
+
+ return result;
+}
+
+// Bug in sqrfree_yun (fixed 2016-02-02).
+static unsigned exam_paranoia24()