def Smallest_Prime_Factor(N):
    """ 0,1,2,...,N の最小の素因数のリスト (0,1 については 1 にしている)
    """

    if N==0:
        return [1]

    N=abs(N)
    L=list(range(N+1))
    L[0]=L[1]=1

    x=4
    while x<=N:
        L[x]=2
        x+=2

    x=9
    while x<=N:
        if L[x]==x:
            L[x]=3
        x+=6

    x=5
    Flag=0
    while x*x<=N:
        if L[x]==x:
            y=x*x
            while y<=N:
                if L[y]==y:
                    L[y]=x
                y+=x<<1
        x+=2+2*Flag
        Flag^=1

    return L

def Faster_Prime_Factorization(N,L):
    """ Smallest_Prime_Factors(N)で求めたリストを利用して, N を高速素因数分解する.

    L: Smallest_Prime_Factors(N)で求めたリスト
    """
    if N==0:
        return [[0,1]]
    elif N>0:
        D=[]
    else:
        D=[[-1,1]]
        N=abs(N)

    while N>1:
        a=L[N]
        k=0
        while L[N]==a:
            k+=1
            N//=a
        D.append([a,k])
    return D

def Divisors_from_Prime_Factor(P,sorting=False):
    X=[1]
    for p,e in P:
        q=1
        n=len(X)
        for _ in range(e):
            q*=p
            for j in range(n):
                X.append(X[j]*q)

    if sorting:
        X.sort()

    return X

#==================================================
A,B,S=map(int,input().split())

L=Smallest_Prime_Factor(S)

Ans=0
for s in range(1,S+1):
    D=Faster_Prime_Factorization(s,L)
    for a in Divisors_from_Prime_Factor(D):
        b=s//a

        Ans+=max(0,A-a+1)*max(0,B-b+1)

print(Ans)