import sys
input=sys.stdin.readline

d = int(input())
a, b = map(int, input().split())

cost = []
if a != 0 and b != 0:
    for x in range(d):
            cost.append(x*a+(d-x)*b)
    print(min(cost))
if a == 0 or b == 0:
    print(0)