import sys
from collections import defaultdict, Counter, deque
from itertools import permutations, combinations, product, combinations_with_replacement, groupby, accumulate
import operator
from math import sqrt, gcd, factorial
# from math import isqrt, prod,comb  # python3.8用(notpypy)
#from bisect import bisect_left,bisect_right
#from functools import lru_cache,reduce
#from heapq import heappush,heappop,heapify,heappushpop,heapreplace
#import numpy as np
#import networkx as nx
#from networkx.utils import UnionFind
#from numba import njit, b1, i1, i4, i8, f8
#from scipy.sparse import csr_matrix
#from scipy.sparse.csgraph import shortest_path, floyd_warshall, dijkstra, bellman_ford, johnson, NegativeCycleError
# numba例 @njit(i1(i4[:], i8[:, :]),cache=True) 引数i4配列、i8 2次元配列,戻り値i1
def input(): return sys.stdin.readline().rstrip()
def divceil(n, k): return 1+(n-1)//k  # n/kの切り上げを返す
def yn(hantei, yes='Yes', no='No'): print(yes if hantei else no)


def check(s, n, m):
    return len(set(ss % n for ss in s)) == len(set(ss//n for ss in s)) == len(s)


def main():
    mod = 10**9+7
    mod2 = 998244353
    n, m, k = map(int, input().split())
    ans = 0
    ass = 1
    for i in range(k):
        ass *= n*m-i
        ass //= i+1
        assert ass <= 12*10**4
    for choose in combinations(range(n*m), k):
        if check(choose, n, m):
            continue
        if any(check(cc, n, m) for cc in combinations(choose, k-1)):
            continue
        for cc in combinations(choose, k-2):
            if check(cc, n, m):
                ans += 1
                break
    print(ans)


if __name__ == '__main__':
    main()