For problem statement at 1000-1999/1500-1599/1560-1569/1566/problemC.txt this is a correct solution, but verifier at 1000-1999/1500-1599/1560-1569/1566/verifierC.go ends with All tests passed can you fix the verifier? ```go
package main

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

func single(x int) int {
	if x == 0 {
		return 1
	}
	if x == 2 {
		return 0
	}
	return 2
}

func pair(x, y int) int {
	if x == 0 && y == 0 {
		return 1
	}
	if x == 2 && y == 2 {
		return 0
	}
	return 2
}

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 int
		var a, b string
		fmt.Fscan(in, &n, &a, &b)

		s := make([]int, n)
		for i := 0; i < n; i++ {
			s[i] = int(a[i]-'0') + int(b[i]-'0')
		}

		dp := make([]int, n+1)
		for i := 0; i < n; i++ {
			v := dp[i] + single(s[i])
			if v > dp[i+1] {
				dp[i+1] = v
			}
			if i+1 < n {
				v = dp[i] + pair(s[i], s[i+1])
				if v > dp[i+2] {
					dp[i+2] = v
				}
			}
		}

		fmt.Fprintln(out, dp[n])
	}
}
```