import sys
sys.setrecursionlimit(1000000)
def debug(*args, **kwargs):
    import os
    if os.getenv('DEBUG'): print(*args, **kwargs, file=sys.stderr)

def input():
    return sys.stdin.readline()[:-1]

def int0(s: str) -> int:
    return int(s) - 1

def main(_=0):
    d = int(input())
    a, b = map(int, input().split())

    ans = 1001001001
    for x in range(d+1):
        ans = min(ans, x * a + (d - x) * b)
    print(ans)

def as_input(s: str) -> None:
    import io
    global input
    f = io.StringIO(s)
    input = lambda: f.readline().rstrip()
    return None

sample1 = """10
20 20
"""
sample2 = """5
0 100
"""
def test():
    """
    >>> main(as_input(sample1))
    200
    >>> main(as_input(sample2))
    0
    """
    pass

if __name__ == '__main__':
    main()