Reducing the process time of the sum of numbers code in Go

I wrote this code, but the code test site rejected due to process time. To reduce time, I used Two pointers algorism, and Goroutine(I am not sure I used it correctly). But still that site rejected with the same reason. Is there any improvement solution to pass this? How can I reduce processing time.
Please review my code. Thank you for your support!

Problem description

sequence of N numbers A[1], A[2], … , A[N] exists. The sum of numbers from i to j in this sequence A[i]+A[i+1]+… Write a program to find the number of cases where +A[j-1]+A[j] becomes M.

input

In the first line, N(1≤N≤10,000) and M(1≤M≤300,000,000) are given. The next line contains A[1], A[2], … , A[N] is given, separated by spaces. Each A[x] is a natural number not exceeding 30,000.

Print

the number of cases on the first line.

Example

• input 1 :

  4 2

  1 1 1 1

• output 1:

  3

• input 2 :

  10 5

  1 2 3 4 2 5 3 1 1 2

• output 2 :

  3

package main

import "fmt"

func main() {
	var n int //numbers
	var m int //target sum

	c := make(chan []int)
	d := make(chan int)

	fmt.Scanf("%d %d\n", &n, &m)
	arr := make([]int, n)
	go ReadN(arr, n, c)
	go checker(<-c, n, m, d)
	fmt.Print(<-d)
}

func ReadN(arr []int, n int, c chan<- []int) {
	for i := 0; i < n; i++ {
		fmt.Scan(&arr[i])
	}
	c <- arr
}

func checker(arr []int, n, m int, d chan<- int) {
	var start int
	var end int
	var sum int
	var result int

	for start < n {
		if sum > m || end == n {
			sum -= arr[start]
			start++
		} else {
			sum += arr[end]
			end++
		}
		if sum == m {
			result++
		}
	}
	d <- result
}

Problem was from Scan and Scanf. It doesn't do any buffering, which makes it very slow if you get a lot of input. So I changed all Scan, Scanf to Fscan, Fscanf. Instead, I used bufio package. However, if you are not satisfied with the speed even with Fscanf(), you should seriously consider using a Scanner.
See below code.

package main

import (
	"bufio"
	"fmt"
	"os"
)

func main() {
	var n int //numbers
	var m int //target sum
	var bufin *bufio.Reader = bufio.NewReader(os.Stdin)

	fmt.Fscanf(bufin, "%d %d\n", &n, &m)
	arr := make([]int, n)
	arr = ReadN(arr, n, bufin)
	result := checker(arr, n, m)
	fmt.Print(bufout, result)
}

func ReadN(arr []int, n int, bufin *bufio.Reader) []int {
	for i := 0; i < n; i++ {
		fmt.Fscan(bufin, &arr[i])
	}
	return arr
}

func checker(arr []int, n, m int) int {
	var start int
	var end int
	var sum int
	var result int

	for start < n {
		if sum > m || end == n {
			sum -= arr[start]
			start++
		} else {
			sum += arr[end]
			end++
		}
		if sum == m {
			result++
		}
	}
	return result
}

You can solve this type of question using prefix-sum algorithm, which can do this in O(n) time and space.
You can also refer to this article.

For practice on this type of questions, refer this