#pragma GCC target("avx2")
#pragma GCC optimize("O3")
#pragma GCC optimize("unroll-loops")
#include <bits/stdc++.h>

int ri() {
	int n;
	scanf("%d", &n);
	return n;
}
int64_t dp[100001];
int main() {
  int k = ri(), n = ri();
  int a[n];
  for (int i = 0; i < n; i++) a[i] = ri();
  dp[0] = 1;
  int head = n;
  for (int i = 0; i < k; i++) {
    int cur = dp[i] % 1000000007;
    while (head && i + a[head - 1] > k) head--;
    for (int j = 0; j < head; j++)
      dp[i + a[j]] += cur;
  }
  std::cout << dp[k] % 1000000007 << std::endl;
  return 0;
}