#include <bits/stdc++.h>
using namespace std;
vector<int> hot={0,990,1010,1970,2030,2940,3060,3930,4060,4970,5030,5990,6010,7000};
int main(){
    int a,b,n,x;
    cin>>a;
    cin>>b;
    cin>>n;
    for(int i=14;i<n+14;i++){
    	cin>>x;
        hot.push_back(x);
	}
	sort(hot.begin(),hot.end());
	int len=hot.size();
	vector<int> dp(35,0);       //定义dp[i] 为 到达第I个旅馆时，总共的旅行方案 
	dp[0]=1;
	for(int i=1;i<len;i++){
		for(int j=0;j<i;j++){
			if(hot[i] - hot[j] >=a &&hot[i] - hot[j] <= b){
				dp[i] +=dp[j];
			}
		}
	}
	
	 cout<<dp[13+n];
	
	return 0;
}