#include <iostream>
using namespace std;
typedef long long ll;
ll n,a,b,c,s,ans,MOD=1e9+7,bi[300001],bi5[300001],L,w[300001];
ll f(ll x,ll y){
    if(y==0)return 1;
    if(y%2==0)return f(x,y/2)*f(x,y/2)%MOD;
    return x*f(x,y-1)%MOD;
}
ll comb(ll x,ll y){
    return bi[x]*bi5[x-y]%MOD*bi5[y]%MOD;
}
int main(void){
    cin>>a>>b>>c;
    s=a+b+c;
    bi[0]=1;
    bi5[0]=1;
    w[0]=1;
    for(int i=1;i<=s;i++){
        w[i]=w[i-1]*2%MOD;
        bi[i]=bi[i-1]*i%MOD;;
        bi5[i]=f(bi[i],1e9+5);
    }
    for(int i=2;i<=s-c;i++){
        L=comb(s-c-1,b);
        if(s-i-c>=b)L-=comb(s-i-c,b);
        ans+=L*w[s-i-1]%MOD*comb(s-i-1,c-1)%MOD;
        ans%=MOD;
        ans+=L*(w[s-i-1]-1)%MOD*comb(s-i-2,c-2)%MOD;
        ans%=MOD;
    }
    cout<<(ans+MOD)%MOD<<endl;
}