C++ :

#include <iostream>
using namespace std;

const int mod=1000000007;

int n,a,b,c;
int jiyi[200010];   //顾名思义，记忆化数组

int baosou(int dangqiann)   //求n为dangqiann时有多少种操作序列
{
	if(dangqiann<=c)
	{
		return 1;
	}
	if(jiyi[dangqiann])
	{
		return jiyi[dangqiann];
	}
	return jiyi[dangqiann]=(baosou(dangqiann-a)+baosou(dangqiann-b))%mod;
}

int main()
{
	cin>>n>>a>>b>>c;
	cout<<baosou(n);
	return 0;
}