var first , second  int
   //  var second int

   _,err :=  fmt.Scanf("%d", &first)
     if err != nil {

           fmt.Printf("%d is not  a valid number", first)
           os.Exit(1)
        } else {
           fmt.Printf("%d", first)
      }
      fmt.Println(" \nPlease enter the second integer ")
     _,err2 := fmt.Scanf("%d", &second)

       if err2 != nil {
          fmt.Println("second number is not a valid numnber , exiting the program")

         os.Exit(1)
       }

         sum := first + second
         fmt.Printf("Sum of %d and %d is %d" , first,second ,sum)



}

Output

 Please enter the first integer
4.5
4
Please enter the second integer
Sum of 4 and 5 is 9