#include<bits/stdc++.h>
using namespace std;
#define fs first
#define sc second
#define pb push_back
#define mp make_pair
#define eb emplace_back
#define ALL(A) A.begin(),A.end()
#define RALL(A) A.rbegin(),A.rend()
typedef long long 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 T> T gcd(T a,T b){return b?gcd(b,a%b):a;}
const LL mod=1000000007;
const LL LINF=1LL<<60;
const int INF=1<<30;
int dx[]={1,0,-1,0,1,-1,1,-1};
int dy[]={0,1,0,-1,1,-1,-1,1};

vector<LL> fact;
vector<LL> inver(1000001);
 
LL combi(int n,int r){
    if(n<r||n<0||r<0) return 0;
    return fact[n]%mod*inver[n-r]%mod*inver[r]%mod;
}
 
 
LL fpow(LL a, LL n){
    LL x = 1;
    while(n > 0){
        if(n&1){
            x=x*a%mod;
        }
        a=a*a%mod;
        n >>= 1;
    }
    return x;
}
 
void set_combi(){
    LL s=1;
    fact.push_back(1);
    for(int i=1;i<=1000000;i++){
        s*=i;
        s%=mod;
        fact.push_back(s);
    }
    inver[1000000]=fpow(fact[1000000],mod-2);
    for(int i=999999;i>=0;i--){
        inver[i]=inver[i+1]*(i+1)%mod;
    }
}
 



int main(){
    set_combi();
    LL a,b,c;cin >> a >> b >> c;
    LL n = a + b + c;
    vector<LL> p(n + 1, 0);
    vector<LL> cnt(n + 1, 0);
    for (int i = c; i <= n-2; i++) {
        LL t = (combi(n - c - 1, b) - combi(i - c, b) + mod)%mod;
        cnt[i - 1] =  combi(i - 1, c - 1) * t %mod;
        if(i - 2 >= 2) p[i - 2] = combi(i - 2, c - 2) * t %mod;
    }
    for (int i = n-1; i >= 0; i--) {
        p[i] = (p[i] + p[i+1])%mod;
        cnt[i] = (cnt[i] + p[i])%mod;
    }
    LL ans = 0;
    for (int i = 0; i < n; i++) {
        ans = (ans + cnt[i] * fpow(2, i))%mod;
    }
    cout << ans << endl;
    return 0;
}