Let's denote *d*(*n*) as the number of divisors of a positive integer *n*. You are given three integers *a*, *b* and *c*. Your task is to calculate the following sum:

Find the sum modulo 1073741824 (2<sup class="upper-index">30</sup>).
The first line contains three space-separated integers *a*, *b* and *c* (1 ≤ *a*, *b*, *c* ≤ 2000).
from fractions import gcd
a,b,c=list(map(int,input().split()))
ans=0
mod=1073741824
div=[0]*(1000001)
for i in range (1,1000001):
    j=i
    while j<=1000000:
        div[j]+=1
        j+=i
for i in range (1,a+1):
    for j in range (1,b+1):
        for k in range (1,c+1):
            ans+=div[i*j*k]
print(ans%mod)
