python calling funcion to another funcion : this is simplified example of my problem. I need to use variable which i created in first definition in another definition, but putting global before variable dont work. Please can you help me ? 

    x = 10
    def one():
        global x
        a = x +2
        b = a/2
        print (b)
    def two():            
        one()             
        c = int(input())            
    def three()                 :
        global a
        global c           
        d = c + a         
        print(b)
    
    two()         
    three()

