For problem statement at 1000-1999/1600-1699/1670-1679/1676/problemC.txt this is a correct solution, but verifier at 1000-1999/1600-1699/1670-1679/1676/verifierC.go ends with All tests passed can you fix the verifier? package main

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

func abs(x int) int {
	if x < 0 {
		return -x
	}
	return x
}

func main() {
	in := bufio.NewReaderSize(os.Stdin, 1<<20)
	out := bufio.NewWriterSize(os.Stdout, 1<<20)
	defer out.Flush()

	var t int
	fmt.Fscan(in, &t)
	for ; t > 0; t-- {
		var n, m int
		fmt.Fscan(in, &n, &m)
		s := make([]string, n)
		for i := 0; i < n; i++ {
			fmt.Fscan(in, &s[i])
		}
		ans := int(1e9)
		for i := 0; i < n; i++ {
			for j := i + 1; j < n; j++ {
				cur := 0
				for k := 0; k < m; k++ {
					cur += abs(int(s[i][k]) - int(s[j][k]))
				}
				if cur < ans {
					ans = cur
				}
			}
		}
		fmt.Fprintln(out, ans)
	}
}