#include <iostream>
#include <cstdio>
using namespace std;
int n,m,x,cnt,v[405];
void rec(int i,int rez)
{
    if(rez==x)
        cnt++;
    if(i>n*m)
        return;
    rec(i+1,rez+v[i]);
    rec(i+1,rez);
    rec(i+1,rez-v[i]);
}
int main()
{
    freopen("diamant.in","r",stdin);
    freopen("diamant.out","w",stdout);
    scanf("%d%d%d",&n,&m,&x);

    int idx=0;
    for(int i=1;i<=n;i++)
    {
        for(int j=1;j<=m;j++)
            v[++idx]=i*j;
    }
    rec(1,0);
    printf("%d",cnt);


    return 0;
}