#include <fstream>
#include <cstring>
#include <stack>

using namespace std;

ifstream inf("e_also_big.in");
ofstream outf("e_also_big.out");

const int MMAX = 1000000000, NMAX = 10000;

int v[NMAX];
short dp[MMAX + 1];
stack<short> stk;

int main() {
    int n, m, x;
    inf >> m >> n;
    memset(dp, 0x3f, sizeof(dp));
    dp[0] = -1;
    for(int i = 0; i < n; i++) {
        inf >> x;
        for(int j = x; j <= m; j++) {
            if(dp[j] > n && dp[j - x] < i) {
                dp[j] = i;
            }
        }
        v[i] = x;
    }
    int rez, cnt = 0;
    for(int i = m; i >= 0; i--) {
        if(dp[i] < n) {
            rez = i;
            break;
        }
    }
    while(rez) {
        cnt++;
        stk.push(dp[rez]);
        rez -= v[dp[rez]];
    }
    outf << cnt << '\n';
    while(!stk.empty()) {
        outf << stk.top() << ' ';
        stk.pop();
    }
    return 0;
}