#include <iostream>
#include <algorithm>
#include <iomanip>
#include <vector>
#include <queue>
#include <deque>
#include <set>
#include <map>
#include <tuple>
#include <cmath>
#include <numeric>
#include <functional>
#include <cassert>
#include <atcoder/modint>

#define debug_value(x) cerr << "line" << __LINE__ << ":<" << __func__ << ">:" << #x << "=" << x << endl;
#define debug(x) cerr << "line" << __LINE__ << ":<" << __func__ << ">:" << x << endl;

template<class T> inline bool chmax(T& a, T b) { if (a < b) { a = b; return 1; } return 0; }
template<class T> inline bool chmin(T& a, T b) { if (a > b) { a = b; return 1; } return 0; }

using namespace std;
typedef long long ll;

template<typename T>
vector<vector<T>> vec2d(int n, int m, T v){
    return vector<vector<T>>(n, vector<T>(m, v));
}

template<typename T>
vector<vector<vector<T>>> vec3d(int n, int m, int k, T v){
    return vector<vector<vector<T>>>(n, vector<vector<T>>(m, vector<T>(k, v)));
}

template<typename T>
void print_vector(vector<T> v, char delimiter=' '){
    if(v.empty()) {
        cout << endl;
        return;
    }
    for(int i = 0; i+1 < v.size(); i++) cout << v[i] << delimiter;
    cout << v.back() << endl;
}

using mint = atcoder::modint1000000007;

ostream& operator<<(ostream& os, const mint& m){
    os << m.val();
    return os;
}

#define N_MAX 1000002
mint inv[N_MAX],fac[N_MAX],finv[N_MAX];

void init(){
    const ll MOD = mint::mod();
    fac[0]=1;fac[1]=1;
    finv[0]=1;finv[1]=1;
    inv[1]=1;
    for(int i=2;i<N_MAX;i++){
        inv[i]=mint(MOD)-inv[MOD%i]*(MOD/i);
        fac[i]=fac[i-1]*(ll) i;
        finv[i]=finv[i-1]*inv[i];
    }
}

mint comb(ll n, ll r){
    if(n < r){
        return mint(0);
    }else{
        return fac[n]*finv[r]*finv[n-r];
    }
}

/**
 * f(x) = g(x)*h(x) + r(x)となる(h(x), r(x))を求めます
 */ 
template<typename T>
pair<vector<T>, vector<T>> naive_divide(vector<T> f, vector<T> g){
    int n = f.size()-1;
    int m = g.size()-1;
    if(n < m) return make_pair(vector<T>(1, T(0)), f);
    int k = n-m;
    vector<T> h(k+1);
    T iv = T(1)/g[m];
    for(int i = k; i >= 0; i--){
        h[i] = f[i+m]*iv;
        for(int j = 0; j <= m; j++){
            f[i+j] -= g[j]*h[i];
        }
    }
    return make_pair(h, f);
}

mint test(int k){
    mint sum = 0;
    for(int l = k; l <= k+10; l++){
        mint sgn = (k%2 == l%2) ? 1 : -1;
        sum += comb(l, k).val()*sgn;
        cout << sum << ' ';
    }
    cout << endl;
}

mint f(int l, int n){
    mint ans = 0;
    for(int k = l; k <= n; k++){
        mint sgn = (k%2 == l%2) ? 1 : -1;
        ans += sgn*comb(k, l);
    }
    return ans;
}

mint test1(int n){
    int m = n;
    vector<mint> w(m+2);
    for(int r = 0; r <= m+1; r++){
        mint sgn = r%2 == (m+1)%2 ? 1 : -1;
        w[r] = comb(m+1, r)*sgn;
    }
    vector<mint> u = {mint(-2), mint(1)};
    auto [v, r] = naive_divide(w, u);
    for(int l = 1; l <= n; l++){
        cout << v[l] << ' ';
    }
    cout << endl;
    for(int l = 1; l <= n; l++){
        cout << f(l, n) << ' ';
    }
    cout << endl;
}

mint naive(int x, int y, int z){
    mint ans = 0;
    for(int l = 1; l <= x+y+z; l++){
        mint s = comb(x+l-1, l-1)*comb(y+l-1, l-1)*comb(z+l-1, l-1);
        mint sum = f(l, x+y+z);
        ans += sum*s;
        cout << sum << ' ';
    }
    cout << endl;
    return ans;
}

mint solve(int x, int y, int z){
    mint ans = 0;
    int m = x+y+z;
    vector<mint> w(m+2);
    for(int r = 0; r <= m+1; r++){
        mint sgn = r%2 == (m+1)%2 ? 1 : -1;
        w[r] = comb(m+1, r)*sgn;
    }
    vector<mint> u = {mint(-2), mint(1)};
    auto [v, r] = naive_divide(w, u);
    for(int l = 1; l <= x+y+z; l++){
        mint s = comb(x+l-1, l-1)*comb(y+l-1, l-1)*comb(z+l-1, l-1);
        ans += v[l]*s;
    }
    return ans;
}

int main(){
    ios::sync_with_stdio(false);
    cin.tie(0);
    cout << setprecision(10) << fixed;
    init();
    int x, y, z; cin >> x >> y >> z;
    // cout << naive(x, y, z) << endl;
    cout << solve(x, y, z) << endl;
}