package main

import "fmt"

func countTo(n int) <-chan int {
	numbers := make(chan int)
	go func() {
		defer close(numbers)
		for number := 1; number <= n; number++ {
			numbers <- number
		}
	}()
	return numbers
}

func main() {
	sum := 0
	for number := range countTo(5) {
		sum += number
	}
	fmt.Println(sum)
}