a = int(input("输入第一个正整数: "))
b = int(input("输入第二个正整数: "))
temp = a
a = b
b = temp
print("a=", a, "b=", b)

a = int(input("输入第一个正整数: "))
b = int(input("输入第二个正整数: "))
a, b = b, a
print("a=", a, "b=", b)

a = int(input("输入第一个正整数: "))
b = int(input("输入第二个正整数: "))
a = a + b
b = a - b
a = a - b
print("a=", a, "b=", b)

a = int(input("输入第一个正整数: "))
b = int(input("输入第二个正整数: "))
a = b
b = a
print("a=", a, "b=", b)