#include <iostream>

using namespace std;
long long sa[301],sb[301],n,a,b,aux,sumb,suma,s;
int main()
{
    sa[1]=1;
    sb[1]=1;
    cin>>n>>a>>b;
    for(int k=2;k<=n;++k)
    {
        sumb=0;
        suma=0;
        for(int i=a;i>=1;--i)sumb+=sa[i];
        for(int i=a;i>1;--i)
        {
            sa[i]=sa[i-1];
            sa[i]=sa[i]%1000000007;
        }
        for(int i=b;i>=1;--i)suma+=sb[i];
        for(int i=b;i>1;--i)
        {
            sb[i]=sb[i-1];
            sb[i]=sb[i]%1000000007;
        }
        sa[1]=sumb%1000000007;
        sb[1]=suma%1000000007;
    }
    for(int i=a;i>=1;--i)s+=sa[i];
    for(int i=b;i>=1;--i)s+=sb[i];
    s=s%1000000007;
    cout<<s;
    return 0;
}