#include<stdio.h>
#include<stdlib.h>
#include<stdint.h>
#include<inttypes.h>
#include<string.h>
#include<math.h>

typedef int32_t i32;
typedef int64_t i64;

#define MAX(a,b) ((a) > (b) ? (a) : (b))
#define MIN(a,b) ((a) < (b) ? (a) : (b))
#define ABS(a) ((a) > (0) ? (a) : -(a))

void run (void) {
  i32 k, n;
  scanf ("%" SCNi32 "%" SCNi32, &k, &n);
  i32 *x = (i32 *) calloc (n, sizeof (i32));
  for (i32 i = 0; i < n; ++i) {
    scanf ("%" SCNi32, x + i);
  }
  i32 *dp = (i32 *) calloc (k + 1, sizeof (i32));
  dp[0] = 1;
  const i32 mod = 1000000007;
  for (i32 i = 0; i < k; ++i) {
    if (dp[i] == 0) continue;
    for (i32 j = 0; j < n && x[j] <= k - i; ++j) {
      dp[i + x[j]] += dp[i];
      if (dp[i + x[j]] >= mod) {
	dp[i + x[j]] -= mod;
      }
    }
  }
  printf ("%" PRIi32 "\n", dp[k]);
}

int main (void) {
  run ();
  return 0;
}