# Write a Python program to find common elements in three lists using sets 
 # Python3 program to find common elements 
# in three lists using sets
  
def IntersecOfSets(arr1, arr2, arr3):
    # Converting the arrays into sets
    s1 = set(arr1)
    s2 = set(arr2)
    s3 = set(arr3)
      
    # Calculates intersection of 
    # sets on s1 and s2
    set1 = s1.intersection(s2)         #[80, 20, 100]
      
    # Calculates intersection of sets
    # on set1 and s3
    result_set = set1.intersection(s3)
      
    # Converts resulting set to list
    final_list = list(result_set)
    print(final_list)
  
# Driver Code
if __name__ == '__main__' :
      
    # Elements in Array1
    arr1 = [1, 5, 10, 20, 40, 80, 100]
      
    # Elements in Array2
    arr2 = [6, 7, 20, 80, 100]
      
    # Elements in Array3
    arr3 = [3, 4, 15, 20, 30, 70, 80, 120]
      
    # Calling Function
    IntersecOfSets(arr1, arr2, arr3)