Problem:
Score : 100 points

Problem Statement

In AtCoder City, there are three stations numbered 1, 2, and 3.

Each of these stations is operated by one of the two railway companies, A and B. A string S of length 3 represents which company operates each station. If S_i is A, Company A operates Station i; if S_i is B, Company B operates Station i.

To improve the transportation condition, for each pair of a station operated by Company A and one operated by Company B, there will be a bus service connecting them.

Determine if there is a pair of stations that will be connected by a bus service.

Constraints

Each character of S is A or B.

|S| = 3

Input

Input is given from Standard Input in the following format:

S

Output

If there is a pair of stations that will be connected by a bus service, print Yes; otherwise, print No.

Sample Input 1

ABA

Sample Output 1

Yes

Company A operates Station 1 and 3, while Company B operates Station 2.

There will be a bus service between Station 1 and 2, and between Station 2 and 3, so print Yes.

Sample Input 2

BBA

Sample Output 2

Yes

Company B operates Station 1 and 2, while Company A operates Station 3.

There will be a bus service between Station 1 and 3, and between Station 2 and 3, so print Yes.

Sample Input 3

BBB

Sample Output 3

No

Company B operates all the stations. Thus, there will be no bus service, so print No.

Solution in Go (1.14.1) (judge verdict: Accepted)

package main

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

func solve(sc *scanner, wr *bufio.Writer) {
	rs := sc.getRunes()

	ans := "Yes"
	if rs[0] == rs[1] && rs[0] == rs[2] {
		ans = "No"
	}
	fmt.Fprintln(wr, ans)
}

func main() {
	sc := newScanner()
	wr := bufio.NewWriter(os.Stdout)
	maxBufSize := int(1e8)
	sc.Buffer(make([]byte, 4096), maxBufSize)
	sc.Split(bufio.ScanWords)

	solve(sc, wr)
	wr.Flush()
}

// input ------------------------
type scanner struct {
	*bufio.Scanner
}

func newScanner() *scanner {
	sc := bufio.NewScanner(os.Stdin)
	return &scanner{sc}
}
func (sc *scanner) getInt() int {
	sc.Scan()
	ret, err := strconv.Atoi(sc.Text())
	if err != nil {
		panic(err)
	}
	return ret
}
func (sc *scanner) getInt2() (int, int) {
	return sc.getInt(), sc.getInt()
}
func (sc *scanner) getInt3() (int, int, int) {
	return sc.getInt(), sc.getInt(), sc.getInt()
}
func (sc *scanner) getInt4() (int, int, int, int) {
	return sc.getInt(), sc.getInt(), sc.getInt(), sc.getInt()
}
func (sc *scanner) getInts(n int) []int {
	ret := make([]int, n)
	for i := range ret {
		ret[i] = sc.getInt()
	}
	return ret
}
func (sc *scanner) getString() string {
	sc.Scan()
	return sc.Text()
}
func (sc *scanner) getRunes() []rune {
	return []rune(sc.getString())
}
func (sc *scanner) getFloat() float64 {
	sc.Scan()
	ret, err := strconv.ParseFloat(sc.Text(), 64)
	if err != nil {
		panic(err)
	}
	return ret
}
func (sc *scanner) getFloats(n int) []float64 {
	ret := make([]float64, n)
	for i := range ret {
		ret[i] = sc.getFloat()
	}
	return ret
}

// math ----------------------------
func sum(ns ...int) int {
	var sum int
	for _, n := range ns {
		sum += n
	}
	return sum
}

func max(ns ...int) int {
	max := ns[0]
	for i := 1; i < len(ns); i++ {
		if max < ns[i] {
			max = ns[i]
		}
	}
	return max
}

func min(ns ...int) int {
	min := ns[0]
	for i := 1; i < len(ns); i++ {
		if min > ns[i] {
			min = ns[i]
		}
	}
	return min
}

func pow(a, b int) int {
	ret := 1
	for b > 0 {
		if b&1 > 0 {
			ret = ret * a
		}
		a = a * a
		b >>= 1
	}
	return ret
}