For problem statement at 0-999/100-199/140-149/146/problemA.txt this is a correct solution, but verifier at 0-999/100-199/140-149/146/verifierA.go ends with All tests passed can you fix the verifier? package main

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

func main() {
	in := bufio.NewReader(os.Stdin)
	var n int
	var s string
	fmt.Fscan(in, &n, &s)

	sum1, sum2 := 0, 0
	for i := 0; i < n; i++ {
		if s[i] != '4' && s[i] != '7' {
			fmt.Println("NO")
			return
		}
		if i < n/2 {
			sum1 += int(s[i] - '0')
		} else {
			sum2 += int(s[i] - '0')
		}
	}

	if sum1 == sum2 {
		fmt.Println("YES")
	} else {
		fmt.Println("NO")
	}
}