diff --git a/ginac/inifcns_nstdsums.cpp b/ginac/inifcns_nstdsums.cpp
index 2c4061a..94fd9ce 100644
--- a/ginac/inifcns_nstdsums.cpp
+++ b/ginac/inifcns_nstdsums.cpp
@@ -2455,7 +2455,8 @@ lst convert_parameter_Li_to_H(const lst& m, const lst& x, ex& pf)
 {
 	lst res;
 	lst::const_iterator itm = m.begin();
-	lst::const_iterator itx = ++x.begin();
+	lst::const_iterator itx = x.begin();
+	++itx;
 	int signum = 1;
 	pf = _ex1;
 	res.append(*itm);
@@ -3277,7 +3278,8 @@ static ex H_eval(const ex& m_, const ex& x)
 		pos1 = *m.begin();
 		p = _ex1;
 	}
-	for (lst::const_iterator it = ++m.begin(); it != m.end(); it++) {
+	lst::const_iterator it = m.begin();
+	for (++it; it != m.end(); ++it) {
 		if ((*it).info(info_flags::integer)) {
 			if (step == 0) {
 				if (*it > _ex1) {
