#include <bits/stdc++.h>
using namespace std;

int a, b, n, ans[40];
int r[40] = {0,990,  1010, 1970, 2030, 2940, 3060,
             3930, 4060, 4970, 5030, 5990, 6010, 7000};
int main() {
    cin >> a >> b >> n;
    for (int i = 14; i < 14 + n; i++) cin >> r[i];
    sort(r, r + 14 + n);
    ans[0] = 1;
    for (int i = 1; i < 14 + n; i++) {
        for (int j = 0; j < i; j++) {
            if (r[i] - r[j] >= a && r[i] - r[j] <= b) {
                ans[i] += ans[j];
            }
        }
    }
    cout << ans[13 + n] << endl;
    return 0;
}