import sys

sys.setrecursionlimit(10 ** 8)
ini = lambda: int(sys.stdin.readline())
inm = lambda: map(int, sys.stdin.readline().split())
inl = lambda: list(inm())
ins = lambda: sys.stdin.readline().rstrip()
debug = lambda *a, **kw: print("\033[33m", *a, "\033[0m", **dict(file=sys.stderr, **kw))


V, T, P = inm()


def solve():
    v = V * (P + 1)

    def is_ok(k):
        return (T - 1) * k <= v

    ok = 0
    ng = v * 2
    while ng - ok > 1:
        mid = (ok + ng) // 2
        if is_ok(mid):
            ok = mid
        else:
            ng = mid
    return v + ok + 1


print(solve())