diff --git a/exotica_core/src/planning_problem.cpp b/exotica_core/src/planning_problem.cpp
index 672eabe269..eccb9041d0 100644
--- a/exotica_core/src/planning_problem.cpp
+++ b/exotica_core/src/planning_problem.cpp
@@ -296,7 +296,7 @@ std::pair<std::vector<double>, std::vector<double>> PlanningProblem::GetCostEvol
 
 int PlanningProblem::GetNumberOfIterations() const
 {
-    return static_cast<int>(std::get<0>(GetCostEvolution())).size();
+    return static_cast<int>(std::get<0>(GetCostEvolution()).size());
 }
 
 double PlanningProblem::GetCostEvolution(int index) const