def cont(x,M):

    ret = 0
    div = M
    while x >= div:
        ret += x // div
        div *= M
    return ret

N,K,M = map(int,input().split())

q = {}
for i in range(2,10**6+1):

    if M % i == 0:
        q[i] = 0
        while M % i == 0:
            M //= i
            q[i] += 1

if M != 1:
    q[M] = 1

ans = float("inf")
for mod in q:
    ans =  min( ans , (cont(N,mod) - cont(K,mod) - cont(N-K,mod)) // q[mod] )
print (ans)