golang, co-prime array

coprime.go

package main

import (
	"bufio"
	"os"
	"strconv"
	"strings"
)

var scanner *bufio.Scanner = bufio.NewScanner(os.Stdin)
var writer *bufio.Writer = bufio.NewWriter(os.Stdout)
var count int = 0
var rel_slice []string

func main() {
	var buff int64
	defer writer.Flush()
	scanner.Scan()
	scanner.Scan()
	str_slice := strings.Split(scanner.Text(), " ")
	for iter, char := range str_slice {
		int_from_char, _ := strconv.ParseInt(char, 10, 64)
		if iter == 0 {
			rel_slice = append(rel_slice, strconv.FormatInt(int_from_char, 10))
			buff = int_from_char
			continue
		}
		if gcd(buff, int_from_char) != 1 {
			for gcd(buff, int_from_char) != 1 {
				buff++
			}
			count++
			rel_slice = append(rel_slice, strconv.FormatInt(buff, 10), strconv.FormatInt(int_from_char, 10))
		} else {
			rel_slice = append(rel_slice, strconv.FormatInt(int_from_char, 10))
		}
		buff = int_from_char
	}
	writer.WriteString(strconv.Itoa(count) + "\n")
	writer.WriteString(strings.Join(rel_slice, " "))
}

func gcd(x, y int64) int64 {
	for y != 0 {
		x, y = y, x%y
	}
	return x
}