package main

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

var sc = bufio.NewScanner(os.Stdin)
var out = bufio.NewWriter(os.Stdout)

func main() {
	buf := make([]byte, 1024*1024)
	sc.Buffer(buf, bufio.MaxScanTokenSize)
	sc.Split(bufio.ScanWords)

	n, a, b := nextInt(), nextInt(), nextInt()
	// 1, -1, 1, -1, ....
	a1 := -a*(n-1) - b*(n%2)
	// 1, 1, 1, 1, ....
	a2 := a*(n-1) - b*n
	ans := Min(a1, a2)
	PrintInt(ans)
}

func nextInt() int {
	sc.Scan()
	i, _ := strconv.Atoi(sc.Text())
	return i
}

func PrintInt(x int) {
	defer out.Flush()
	fmt.Fprintln(out, x)
}

func Min(x, y int) int {
	if x < y {
		return x
	}
	return y
}