Bubble sort program in Python

bubblesort

def swap(p,q):
    return q,p

a=[]

x=int(input("Enter the number of elements you want to sort : "))
i=0
while (i < x):
    y=int(input("Enter element " + str(i+1) + " : "))
    a.append(y)
    i+=1

print (a)
i=1
j=0

while (i<x):
    j = 0
    k = (x-i-1)
    while (j < x-i):
        if (a[j] > a[j+1] or a[k] < a[k-1] ):
            a[j],a[j+1]=swap(a[j],a[j+1])
        j+=1
        k-=1
    i+=1

print (a)