#pragma GCC optimize("O3")
#pragma GCC optimize("unroll-loops")
#pragma GCC target("avx2")

#include <stdio.h>
typedef long long int ll;

ll dp[200000];
ll a[200000];
ll MOD = 1000000007;
int main(void){
    ll k, n;
    ll i, j;
    scanf("%lld%lld", &k, &n);
    for (i = 0; i < n; i++) scanf("%lld", &a[i]);
    
    dp[0] = 1;
    for (i = 1; i <= k; i++) {
        for (j = 0; j < n; j++) {
            if (a[j] > i) break;
            dp[i] = (dp[i] + dp[i - a[j]]) % MOD;
        }
    }
    
    printf("%llu\n", dp[k]);
}