# import sys
# input = sys.stdin.readline
def mp():return map(int,input().split())
def lmp():return list(map(int,input().split()))
import math
import bisect
from copy import deepcopy as dc
from itertools import accumulate
from collections import Counter, defaultdict, deque
def ceil(U,V):return (U+V-1)//V
def modf1(N,MOD):return (N-1)%MOD+1
inf = int(1e30)
mod = 998244353

d = int(input())
a,b = mp()
ans = inf
for i in range(d+1):
    ans = min(ans, i*a+(d-i)*b)
print(ans)