title: find unique element in go slice which is filled stdin
body: <p>need to output to the terminal a int that does not have a pair. My problem is that I don’t understand how not to output a number when it is no longer unique.</p>
  
  <p>here is my code:</p>
  
  <pre><code>import "fmt"
  
  func main() {
      var arr []int
      var unique int
      var input int
      for true {
          keys := make(map[int]bool)
          fmt.Scan(&amp;input)
          arr = append(arr, input)
          fmt.Println(arr)
          for _, entry := range arr {
              if _, value := keys[entry]; !value {
                  keys[entry] = false
                  unique = entry
                  fmt.Println("UNIQ", unique)
              }
          }
      }
  }
  </code></pre>