package main
import ( "fmt"
        "regexp"
        )

func main(){
	// your code goes here
	test := `(?i)\b(co.)(?:\s|$)`
	re := regexp.MustCompile(test)
	matches := re.FindAllStringSubmatch("co. is a secret shortcut ", -1)
	for _, match := range matches {
		fmt.Printf("'%s'", match[1])
	}
}