mod = 1000000007
eps = 10**-9


def main():
    import sys
    input = sys.stdin.readline

    def PrimeDecomposition(N):
        ret = {}
        n = int(N ** 0.5)
        for d in range(2, n + 1):
            while N % d == 0:
                if d not in ret:
                    ret[d] = 1
                else:
                    ret[d] += 1
                N //= d
            if N == 1:
                break
        if N != 1:
            ret[N] = 1
        return ret

    def f(n, m):
        ret = 0
        for i in range(1, 100):
            x = n // (m ** i)
            if x == 0:
                break
            ret += x
        return ret

    N, K, M = map(int, input().split())
    ans = float("inf")
    for p in PrimeDecomposition(M):
        ans = min(ans, (f(N, p) - f(K, p) - f(N - K, p)) // f(M, p))
    print(ans)


if __name__ == '__main__':
    main()