Python Program to Know Atomic Mass of First 30 Elements

print("PROGRAM TO KNOW ATOMIC MASS OF FIRST 30 ELEMENTS")
a=1
while (a>0):
    ele_nme=input("Enter the Name of the element: ")
    atm_no=int(input("Enter the 'ATOMIC NUMBER': "))
    L3=["Argon","Titanium","Chromium","Iron"] 
    L4=["Scandium","Nickel"] 
    L5=["Vanadium","Manganese","Cobalt","Copper","Zinc"] 
    evenorodd=atm_no%2
    if ele_nme=="hydrogen":
        print("The",ele_nme,"'s","ATOMIC MASS IS :","1")
        
    elif ele_nme=="Beryllium":
        print("The",ele_nme,"'s","ATOMIC MASS IS :", atm_no*2+1)
        
    elif ele_nme=="Nitrogen":
        print("The",ele_nme,"'s","ATOMIC MASS IS :", atm_no*2)

    elif ele_nme in L3:
        print("The",ele_nme,"'s","ATOMIC MASS IS :", atm_no*2+4)

    elif ele_nme in L4:
        print("The",ele_nme,"'s","ATOMIC MASS IS :", atm_no*2+3)

    elif ele_nme in L5:
        print("The",ele_nme,"'s","ATOMIC MASS IS :", atm_no*2+5)

    elif evenorodd==0:
        print("The",ele_nme,"'s","ATOMIC MASS IS :", atm_no*2)

    elif evenorodd==1:
        print("The",ele_nme,"'s","ATOMIC MASS IS :", atm_no*2+1)
        
    else:
        print("Enter the value of ATOMIC NUMBER only in 'integer form'")
        a+=1

Output:

PROGRAM TO KNOW ATOMIC MASS OF FIRST 30 ELEMENTS
Enter the Name of the element: hydrogen
Enter the 'ATOMIC NUMBER': 1
The hydrogen 's ATOMIC MASS IS : 1
Enter the Name of the element: