For problem statement at 0-999/500-599/590-599/591/problemB.txt this is a correct solution, but verifier at 0-999/500-599/590-599/591/verifierB.go ends with All 100 tests passed can you fix the verifier? package main

import (
	"bufio"
	"os"
)

func main() {
	scanner := bufio.NewScanner(os.Stdin)
	scanner.Split(bufio.ScanWords)
	scanner.Buffer(make([]byte, 1024*1024), 10*1024*1024)

	scanner.Scan()
	scanner.Scan()
	scanner.Scan()
	s := append([]byte(nil), scanner.Bytes()...)

	mapping := make([]byte, 26)
	for i := 0; i < 26; i++ {
		mapping[i] = byte('a' + i)
	}

	for scanner.Scan() {
		u := scanner.Bytes()[0]
		scanner.Scan()
		v := scanner.Bytes()[0]

		if u != v {
			for j := 0; j < 26; j++ {
				if mapping[j] == u {
					mapping[j] = v
				} else if mapping[j] == v {
					mapping[j] = u
				}
			}
		}
	}

	for i := 0; i < len(s); i++ {
		s[i] = mapping[s[i]-'a']
	}

	os.Stdout.Write(append(s, '\n'))
}