diff --git a/src/genetic_algorithm.py b/src/genetic_algorithm.py
index 1a170be..dedba02 100644
--- a/src/genetic_algorithm.py
+++ b/src/genetic_algorithm.py
@@ -156,24 +156,26 @@ def tournament_selection(m, population):
 
 def generational_replacement(previous_population, current_population):
     new_population = current_population
-    best_previous_individual = max(previous_population, key=lambda x: x.fitness)
+    best_previous_individual = max(previous_population, key=lambda x: all(x.fitness))
     if best_previous_individual not in new_population:
-        worst_index = new_population.index(min(new_population, key=lambda x: x.fitness))
+        worst_index = new_population.index(
+            min(new_population, key=lambda x: all(x.fitness))
+        )
         new_population[worst_index] = best_previous_individual
     return new_population
 
 
 def get_best_elements(population):
-    first_index = population.index(max(population, key=lambda x: x.fitness))
+    first_index = population.index(max(population, key=lambda x: all(x.fitness)))
     population.pop(first_index)
-    second_index = population.index(max(population, key=lambda x: x.fitness))
+    second_index = population.index(max(population, key=lambda x: all(x.fitness)))
     return first_index, second_index
 
 
 def get_worst_elements(population):
-    first_index = population.index(min(population, key=lambda x: x.fitness))
+    first_index = population.index(min(population, key=lambda x: all(x.fitness)))
     population.pop(first_index)
-    second_index = population.index(min(population, key=lambda x: x.fitness))
+    second_index = population.index(min(population, key=lambda x: all(x.fitness)))
     return first_index, second_index