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

struct FastI {
	char buf[1000000];
	char *ptr = buf, *end;
	void read_() { end = (ptr = buf) + fread(buf, 1, sizeof(buf) - 1, stdin); }
	FastI () { read_(); }
	void inc() { if (++ptr == end) read_(); }
	template<typename value_t> value_t read() {
		bool neg = false;
		value_t res = 0;
		while ((*ptr < '0' || *ptr > '9') && *ptr != '-') inc();
		if (*ptr == '-') neg = true, inc();
		while (*ptr >= '0' && *ptr <= '9') res = res * 10 + *ptr - '0', inc();
		return neg ? -res : res;
	}
} fasti;
#define ri fasti.read<int>
#define rs64 fasti.read<int64_t>


#define N 100030
#define MOD 1000000007

using vec_t = __m256i;

__attribute__((aligned(32))) uint32_t table[N], dp[N];

void calc0() {
	dp[0] = 1;
	
	vec_t mod2 = _mm256_set1_epi32(2 * MOD);
#	define BLOCK 14
	for (int i = 0; i < N; i += BLOCK) {
		for (int j = i; j < i + BLOCK; j++) if (dp[j] >= MOD) dp[j] -= MOD;
		for (int j = i; j < i + BLOCK; j++) for (int k = j + 1; k < i + BLOCK; k++) if (table[k - j]) {
			dp[k] += dp[j];
			if (dp[k] >= MOD) dp[k] -= MOD;
		}
#		define DEF_A(x) vec_t a##x = _mm256_set1_epi32(dp[i + x])
		DEF_A(0); DEF_A(1); DEF_A(2); DEF_A(3); DEF_A(4); DEF_A(5); DEF_A(6);
		DEF_A(7); DEF_A(8); DEF_A(9); DEF_A(10); DEF_A(11); DEF_A(12); DEF_A(13);
		
		for (int j = BLOCK; j < N - i - 8; j += 8) {
			vec_t added = _mm256_load_si256((vec_t *) (dp + i + j));
#			define MASKED(x) _mm256_and_si256(a##x, _mm256_loadu_si256((vec_t *) (table + j - x)))
#			define ADD(x1, x2) added = _mm256_add_epi32(_mm256_add_epi32(MASKED(x1), MASKED(x2)), added), \
							   added = _mm256_max_epi32(added, _mm256_sub_epi32(added, mod2))
			ADD(13, 12); ADD(11, 10); ADD(9, 8); ADD(7, 6); ADD(5, 4); ADD(3, 2); ADD(1, 0);
			_mm256_storeu_si256((vec_t *) (dp + i + j), added);
		}
	}
}

int main() {
	int k = ri();
	int n = ri();
	for (int i = 0; i < n; i++) table[ri()] = (uint32_t) -1;
	calc0();
	printf("%d\n", (int) dp[k]);
	return 0;
}