#define _USE_MATH_DEFINES
#include <bits/stdc++.h>
using namespace std;

//template
#define rep(i,a,b) for(int i=(a);i<(b);i++)
#define rrep(i,a,b) for(int i=(a);i>(b);i--)
#define ALL(v) (v).begin(),(v).end()
typedef long long int ll; typedef pair<ll, ll> P;
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; }
template<typename A,size_t N,typename T>void Fill(A(&array)[N],const T &val){fill((T*)array, (T*)(array+N), val);}
const int inf = INT_MAX / 2; const ll INF = LLONG_MAX / 2;
//template end

int mod = 1e9+7;
struct Mint {
    int val;
    Mint inv() const {
        int tmp, a = val, b = mod, x = 1, y = 0;
        while(b) tmp = a / b, a -= tmp * b, swap(a, b), x -= tmp * y, swap(x, y);
        return Mint(x);
    }
public:
    Mint() :val(0) {}
    Mint(ll x) :val(x >= 0 ? x % mod : x % mod + mod) {}
    int mtoi() { return this->val; }
    Mint pow(ll t) { Mint res = 1,b = *this; while(t){if(t&1)res *= b;b *= b;t >>= 1;}return res; }
    Mint& operator+=(const Mint& x) { if ((val += x.val) >= mod) val -= mod; return *this; }
    Mint& operator-=(const Mint& x) { if ((val += mod - x.val) >= mod) val -= mod; return *this; }
    Mint& operator*=(const Mint& x) { val = (ll)val * x.val % mod; return *this; }
    Mint& operator/=(const Mint& x) { return *this *= x.inv(); }
    bool operator==(const Mint& x) const { return val == x.val; }
    bool operator!=(const Mint& x) const { return val != x.val; }
    bool operator<(const Mint& x) const { return val < x.val; }
    bool operator<=(const Mint& x) const { return val <= x.val; }
    bool operator>(const Mint& x) const { return val > x.val; }
    bool operator>=(const Mint& x) const { return val >= x.val; }
    Mint operator+(const Mint& x) const { return Mint(*this) += x; }
    Mint operator-(const Mint& x) const { return Mint(*this) -= x; }
    Mint operator*(const Mint& x) const { return Mint(*this) *= x; }
    Mint operator/(const Mint& x) const { return Mint(*this) /= x; }
};
struct factorial {
    vector<Mint> Fact, Finv;
public:
    factorial(int maxx) {
        Fact.resize(maxx+1,Mint(1)),Finv.resize(maxx+1); rep(i,0,maxx)Fact[i+1]=Fact[i]*Mint(i+1);
        Finv[maxx]=Mint(1)/Fact[maxx]; rrep(i,maxx,0)Finv[i-1]=Finv[i]*Mint(i);
    }
    Mint fact(int n,bool inv) { if(inv) return Finv[n]; else return Fact[n]; }
    Mint nPr(int n,int r) { if(n<0||n<r||r<0) return Mint(0); else return Fact[n]*Finv[n-r]; }
    Mint nCr(int n,int r) { if(n<0||n<r||r<0) return Mint(0); else return Fact[n]*Finv[r]*Finv[n-r]; }
};

int main(){
    int a,b,c; scanf("%d%d%d",&a,&b,&c);
    int n=a+b+c;
    Mint ans,base=2; factorial fact(300010);
    rep(i,n-a-1,n-1){
        Mint add=fact.nCr(i-1,b-1)*fact.nCr(i-b,c-1),p=base.pow(i);
        p-=1; add*=p; ans+=add;
    }
    printf("%d\n",ans.mtoi());
    return 0;
}