diff --git a/src/main.rs b/src/main.rs
index 2950203..232e1a3 100644
--- a/src/main.rs
+++ b/src/main.rs
@@ -13,8 +13,8 @@ use crate::variations::calculate::get_variations;
 
 
 #[derive(Debug)]
-pub struct ElementNr<'a> {
-    element : &'a Element,
+pub struct ElementNr {
+    element : &'static Element,
     nr : u32
 }
 
diff --git a/src/parse.rs b/src/parse.rs
index c31a8c4..a002f7f 100644
--- a/src/parse.rs
+++ b/src/parse.rs
@@ -2,7 +2,7 @@ use periodic_table::Element;
 use crate::ElementNr;
 
 
-pub fn parse(arg: &String) -> Vec<ElementNr<'static>> {
+pub fn parse(arg: &String) -> Vec<ElementNr> {
     let mut char_before: Option<char> = None;
     let mut element: Option<&Element> = None;
     let mut element_line: Vec<ElementNr> = vec![];
diff --git a/src/variations/calculate.rs b/src/variations/calculate.rs
index 4b55881..5165e17 100644
--- a/src/variations/calculate.rs
+++ b/src/variations/calculate.rs
@@ -2,11 +2,11 @@ use periodic_table::Element;
 
 use crate::ElementNr;
 
-pub struct Variation {
-    longest: Element
+pub struct Variation<'a> {
+    longest: &'a ElementNr,
 }
 
-pub fn get_variations(elements: Vec<ElementNr>) -> Vec<Variation> {
+pub fn get_variations(elements: Vec<ElementNr>) -> Vec<Variation<'static>> {
     let mut variations: Vec<Variation> = vec![];
     
     variations