#include <stdio.h>
#include <algorithm>
#include <math.h>
using namespace std;
const int P = 53, MN = 100010;
const int INF = 1000000007;
const double eps = (1e-7);

int n, p, a[MN], b[MN], d[MN][110], t[MN][110];

main() {
    freopen("in.txt", "r", stdin); freopen("out.txt", "w", stdout);
    //freopen("nails.in", "r", stdin); freopen("nails.out", "w", stdout);
    scanf("%d%d", &n, &p);
    for (int i = 1; i <= n; i++) {
        scanf("%d", &a[i]);
    }
    for (int i = 1; i <= p; i++) {
        scanf("%d", &b[i]);
    }
    for (int i = 1; i <= n; i++) {
        int k = -1;
        for (int j = 1; j <= p; j++) {
            while (a[k + 1] <= a[i] - b[j]) k++;
            d[i][j] = d[i][j - 1];
            t[i][j] = -2;
            if (d[i-1][j] > d[i][j]) {
                d[i][j] = d[i-1][j];
                t[i][j] = -1;
            }
            if (k >= 0 && d[i][j] < d[k][j - 1] + 1) {
                d[i][j] = d[k][j - 1] + 1;
                t[i][j] = k;
            }
            //printf ("%d ", d[i][j]);
        }//printf("\n");
    }
    printf ("%d\n", d[n][p]);
    while (n > 0 && p > 0) {
        //printf("%d %d %d\n", n, p, t[n][p]);
        if (t[n][p] >= 0) {
            printf("%d %d\n", p, n);
            n = t[n][p];
        }
        else if (t[n][p] == -1) {
            n--;
        }
        else {
            p--;
        }
    }
    return 0;
}