// No.1517 Party Location
package main

import (
	"fmt"
	"math"
)

func main() {
	var d, a, b int
	fmt.Scan(&d, &a, &b)

	ans := math.MaxInt64
	for i := 0; i <= d; i++ {
		ans = min(ans, i*a+(d-i)*b)
	}
	fmt.Println(ans)
}