#Functions
#Write a program that shows how to use functions
#We will write one function that has 2 parameters
#and returns sum of the parameters
#The program reads 4 numbers, and finds sum of firt
#two numbers and sum of second two numbers using function

def main():
	n1=int(input("enter first num "))
	n2=int(input("enter second num "))
	n3=int(input("enter third num "))
	n4=int(input("enter fourth num "))
	#function call:
	func_res1=sum_two(n1, n2)
	func_res2=sum_two(n3, n4)

	print("Sum of n1 and n2 is", func_res1)
	print("Sum of n3 and n4 is", func_res2)


#function name: sum_two
#function parameters: a and b - "INPUTS"
#return value: sum of two parameters - "OUTPUT"

#function definition starts with KEYWORD: def
def sum_two(a,b):
	
	result=a+b
	
	return result 


main()