import std.algorithm;
import std.array;
import std.ascii;
import std.container;
import std.conv;
import std.math;
import std.numeric;
import std.range;
import std.stdio;
import std.string;
import std.typecons;
import core.bitop;

void log(A...)(A arg) {
    stderr.writeln(arg);
}
int size(T)(in T s) {
    return cast(int)s.length;
}

void main() {
    int N; readf("%d\n", &N);
    auto A = readln.chomp.split(" ").map!(to!int).array;
    int M; readf("%d\n", &M);
    auto B = readln.chomp.split(" ").map!(to!int).array;

    auto pos = new int[][M];
    for (int bit = 0; bit < (1<<N); bit++) {
        int sum = 0;
        foreach (int i, a; A) {
            if (bit & (1 << i)) {
                sum += a;
            }
        }
        foreach (int i, b; B) {
            if (b >= sum) {
                pos[i] ~= bit;
            }
        }
    }
    foreach (int i, b; B) {
        auto del = new bool[pos[i].size];
        foreach (j, p; pos[i]) {
            foreach (k, q; pos[i]) {
                if (j == k) continue;
                if ((p & q) == q) {
                    del[k] = true;
                }
            }
        }
        int[] npos;
        foreach (j, p; pos[i]) {
            if (del[j]) continue;
            npos ~= p;
        }
        pos[i] = npos;
    }

    auto dp = new bool[][](1<<N, 1<<M);
    dp[0][0] = true;
    for (int a = 0; a < (1<<N); a++) {
        for (int b = 0; b < (1<<M); b++) {
            if (! dp[a][b]) continue;
            for (int j = 0; j < M; j++) {
                if (b & (1 << j)) continue;
                foreach (p; pos[j]) {
                    dp[a | p][b | (1<<j)] = true;
                }
            }
        }
    }
    int ans = 40;
    for (int b = 0; b < (1<<M); b++) {
        if (dp[(1<<N) - 1][b]) {
            ans = min(ans, popcnt(b));
        }
    }
    if (ans == 40) ans = -1;
    writeln(ans);

}