Exchange the value of the two variable which is already exist is called swapping.
Example -
Before swapping
a=10
b=20
After swapping
a=20
b=10
program -
print("Enter first number")
a=int(input())
print("Enter second number")
b=int(input())
print("Before swapping -")
print(a,b)
a=a+b
b=a-b
a=a-b
print("After swapping -")
print(a,b)
Enter first value
12
Enter second value
13
Before swapping -
12 13
After swapping -
13 12