Adding Variables

[absolum]

Hello! I am working on a program for guitar. This is a rather simple problem but I am new to coding and don't know why the heck this is not working. I tried two ways, as you can see below. Any help is appreciated. Thanks!

E_String = input('What are you fretting on the low E string? ')
A_String = input('What are you fretting on the A string? ')
D_String = input('What are you fretting on the D string? ')
G_String = input('What are you fretting on the G string? ')
B_String = input('What are you fretting on the B string? ')
e_String = input('What are you fretting on the high e string? ')
all_string_sum = (E_String + A_String + D_String + G_String + B_String + e_String)
if all_string_sum == '1':
    print ("E")

Method #2

if E_String + A_String + D_String + G_String + B_String + e_String == '1':
    print("D+")