#program to swap indexes of present to succedinng one or viceversa
list=eval(input("enter a list"))
print(list)
a=len(list)
if a%2!=0:
    a=a-1
for i in range(0,a,2):
    list[i],list[i+1]=list[i+1],list[i]
print("swapped position and the list is",list)