#include <bits/stdc++.h>
using namespace std;
#define int long long
#define stoi stoll
using pii=pair<int,int>;
using vi = vector<int>;
using vvi = vector<vi>;
#define all(c) begin(c),end(c)
#define rall(c) rbegin(c),rend(c)
#define fore(x,c) for(auto &&x:c)
#define rep(i,a,n) for(int i=a,i##len=(int)(n);i<i##len;++i)
#define rrep(i, a, n) for(int i=(int)(n-1);i>=a;--i)
#define sz(c) ((int)c.size())
#define contains(c,x) (c.find(x)!=end(c))
#define inseg(l,x,r) ((l)<=(x)&&(x)<(r))
#define dump(...)
#define pb push_back
#define _ 0
const signed INF_=1001001001; const long long INF=1001001001001001001LL;
const int DX[9]={0,1,0,-1,1,1,-1,-1,0},DY[9]={-1,0,1,0,-1,1,1,-1,0};
template<class T> ostream& operator<<(ostream &os,const vector<T> &v) {
    for (auto i = begin(v); i != end(v); i++) os<<*i<<(i==end(v)-1?"":" ");return os;}
template<class T> istream& operator>>(istream &is,vector<T> &v) {
    for (auto i = begin(v); i != end(v); i++) is>>*i;return is;}
template<class T,class U> istream& operator>>(istream &is, pair<T,U> &p) {
    is>>p.first>>p.second;return is;}
template<class T, class U> bool chmax(T &a,const U &b){return a<b?a=b,1:0;}
template<class T, class U> bool chmin(T &a,const U &b){return a>b?a=b,1:0;}
template <class T> void psum(T& c) {partial_sum(begin(c), end(c), begin(c));}
template<class T> using heap=priority_queue<T,vector<T>,greater<T>>;
struct before_main_function {
    before_main_function() {
        cin.tie(nullptr); ios::sync_with_stdio(0);
        cout << setprecision(15) << fixed;
        // #define endl "\n"
    }
} before_main_function;
//------------------8<------------------------------------8<--------------------

void dump_impl(string s) { assert(s.empty()); }
template <class H, class... T>
void dump_impl(string s, const H &head, const T&... tail) {
    int par = 0;
    rep(i, 0, sz(s)) {
        char ch = s[i];
        if (ch == ',' && par == 0) {
            cerr << " = " << head << ", ";
            dump_impl(s.substr(i + 1), tail...);
            return;
        } else {
            cerr << ch;
            if (ch == '(') par++;
            if (ch == ')') par--;
        }
    }
}
#ifdef dump
    #undef dump
#endif
#define dump(...) do { cerr << "\x1b[33;1m"; dump_impl(#__VA_ARGS__ ",", __VA_ARGS__); cerr << "\x1b[0m" << endl; } while (0)
template <int mod>
class ModInt {
public:
    ModInt() : v(0) {}
    ModInt(int x) : v((x+mod)%mod) {}
    int value() const {return v;}
    const ModInt operator+(const ModInt &r) const { return ModInt(this->v + r.v); }
    const ModInt operator-(const ModInt &r) const { return ModInt(this->v + mod - r.v); }
    const ModInt operator*(const ModInt &r) const { return ModInt(this->v * r.v); }
    const ModInt operator/(const ModInt &r) const { return (*this * (~r)); }
    const ModInt operator^(int k) const { return ModInt(bpow(this->v, k)); }
    const ModInt operator~() const { return ModInt(bpow(this->v, mod-2)); }
    bool operator==(const ModInt &r) const { return this->v == r.v; }
    bool operator!=(const ModInt &r) const { return this->v != r.v; }
    ModInt& operator+=(const ModInt &r) { return *this = *this + r; }
    ModInt& operator-=(const ModInt &r) { return *this = *this - r; }
    ModInt& operator*=(const ModInt &r) { return *this = *this * r; }
    ModInt& operator/=(const ModInt &r) { return *this = *this * (~r); }
private:
    int v;
    int bpow(int a, int b) const {
        int ret = 1;
        while (b > 0) {
            if (b & 1) ret = (ret * a) % mod;
            a = (a * a) % mod;
            b >>= 1;
        }
        return ret;
    }
};
using Mint = ModInt<1000000007>;
ostream& operator<<(ostream &os,Mint v) {
    os<<v.value();
    return os;
}

struct Factorial {
    static constexpr int MAX_N = 2000006;
    vector<Mint> fact, fact_inv;
    Factorial(size_t size = MAX_N) : fact(size), fact_inv(size) {
        fact[0] = fact_inv[0] = 1;
        for (int i = 1; i < MAX_N; ++i) {
            fact[i] = fact[i - 1] * i;
            fact_inv[i] = ~fact[i];
        }
    }
    Mint combination(int N, int R) {
        if (N < 0 || R < 0) return 0;
        if (N < R) return 0;
        return fact[N] * fact_inv[N - R] * fact_inv[R];
    }
    static Mint bin_pow(Mint x, int p) {
        if (x.value() == 0) return x;
        Mint prod = 1;
        while (p > 0) {
            if (p & 1) prod *= x;
            x *= x;
            p >>= 1;
        }
        return prod;
    }
};

signed main() {
    int a, b, c;
    cin >> a >> b >> c;
    int n = a + b + c;

    Factorial fact;

    vector<Mint> sum(n + 1, 0);
    rep(y_len, b + c, n) {
        sum[y_len] = fact.combination((y_len - c) - 1, b - 1);
    }
    psum(sum);

    Mint ans = 0;
    rep(z_len, c, n - 1) {
        Mint tot = ((Mint(2) ^ (z_len - 1)) - Mint(1));
        Mint way = fact.combination(z_len - 2, c - 2);
        Mint tmp = (Mint(2) ^ (z_len - 1)) * fact.combination(z_len - 1, c - 1) + tot * way;
        tmp *= sum[n - 1] - sum[z_len];
        ans += tmp;
    }
    cout << ans.value() << endl;
    return 0;
}