#include "bits/stdc++.h"
using namespace std;
#define fi first
#define se second
#define mp make_pair
#define pii pair<int,int>
#define yes cout<<"YES\n"
#define no cout<<"NO\n"
#define pb push_back
#define sz(x) (int)(x).size()
#define rsz resize
#define ass assign
#define F(i,l,r) for(int i=(l);i<(r);++i)
typedef long long ll;
typedef unsigned long long ull;
typedef long double lld;
template<typename T> using pqg = priority_queue<T, vector<T>, greater<T>>;
#define each(a,x) for(auto a:x)
#define FOR(i,a) for(int i=0;i<(a);i++)
#define ROF(i,a,b) for(int i=(b)-1;i>=(a);i--)
#define eb emplace_back
#define ft front()
#define V vector
void solve(){
ll r,u,n;
cin>>r>>u>>n;
set<ll> st;
F(i,1,r+1){
F(j,1,u+1){
ll prv2=i,prv1=j,cur=j;
F(k,3,n+1){
cur=prv1+prv2;
prv2=prv1;
prv1=cur;
}
st.insert(cur);
}
}
cout<<sz(st)<<'\n';
}
signed main(){
ios_base::sync_with_stdio(0);cin.tie(nullptr);
// #ifndef ONLINE_JUDGE
// freopen("output.txt", "w", stdout);
// freopen("input.txt", "r", stdin);
// freopen("Error.txt", "w", stderr);
// #endif
int tt=1;
//cin>>tt;
while(tt--)solve();
return 0;
}
