#include <bits/stdc++.h>
using namespace std;
#define rep(i, a, b) for(int i = a; i < (b); ++i)
#define all(x) begin(x), end(x)
#define sz(x) (int)(x).size()
typedef long long ll;
typedef pair<int, int> pii;
typedef vector<int> vi;
ll ans = 0;
void solve(ll A,ll B,ll C,bool mode){
    for(ll a=1;a<=min(A,C);a++){
        //a,b,a+b
        //-b,a+b,a
        
        //b <= min(A,B)
        //a+b <= min(B,C);
        //b <= min(B,C) - a
        ll b = min(min(B,C)-a,A);
        if(b>0){
            ans += b - (b >= a);
        }


        //a,b,a+b
        //a+b,-a,b

        //b <= min(B,C)
        //a+b <= min(A,C)
        //b <= min(A,C)-a
        b = min(min(A,C)-a,B);
        if(b>0 && mode){
            ans += b - (b >= a);
        }
    }
   // cout<<ans<<'\n';
}
int main() {
    cin.tie(0)->sync_with_stdio(0);
    cin.exceptions(cin.failbit);
    ll A,B,C;
    cin>>A>>B>>C;

    //cout<<"TES"<<'\n';
    //A B C
    solve(A,B,C,1);
    solve(C,A,B,0);
    ans*=8;
    cout<<ans<<'\n';
}