#include <stdio.h>
#include <stdbool.h>

int max(int a, int b) {
    int v[2] = { a, b };
    return v[b > a];
}

int min(int a, int b) {
    int v[2] = { a, b };
    return v[b < a];
}

int ks[2001][2001], v[2000], w[2000];
bool t[2001][2001];
int main() {
    int c, n;
    while (scanf("%d %d", &c, &n) == 2) {
        for (int i = 0; i < n; i++) {
            scanf("%d %d", &v[i], &w[i]);
        }

        for (int j = 0; j < w[0] && j <= c; j++) {
            ks[0][j] = 0;
            t[0][j] = false;
        }
        for (int j = w[0]; j <= c; j++) {
            ks[0][j] = v[0];
            t[0][j] = true;
        }

        for (int i = 1; i < n; i++) {
            for (int j = 0; j < w[i] && j <= c; j++) {
                ks[i][j] = ks[i - 1][j];
                t[0][j] = false;
            }
            for (int j = w[i]; j <= c; j++) {
                int skip = ks[i - 1][j];
                int take = ks[i - 1][j - w[i]] + v[i];
                ks[i][j] = max(take, skip);
                t[i][j] = take > skip;
            }
        }

        int taken[2000];
        int taken_count = 0;
        int j = c;
        for (int i = n - 1; i >= 0; i--) {
            if (t[i][j]) {
                taken[taken_count++] = i;
                j -= w[i];
            }
        }
        printf("%d\n", taken_count);
        for (int i = taken_count - 1; i >= 0; i--) {
            printf("%d%c", taken[i], i == 0 ? '\n' : ' ');
        }
    }
}