#include <algorithm>
#include <iostream>
#include <vector>
using namespace std;

struct BipartiteMatching {
    int n, timestamp;
    vector<vector<int>> graph;
    vector<int> alive, used, match;
    BipartiteMatching(int n) : \
    n(n), timestamp(0), graph(n), alive(n, 1), used(n, 0), match(n, -1) { }
    void add_edge(int u, int v) {
        graph[u].emplace_back(v);
        graph[v].emplace_back(u);
    }
    bool dfs(int idx) {
        used[idx] = timestamp;
        for (auto &to: graph[idx]) if (alive[to]) {
            int to_match = match[to];
            if (to_match == -1 || (used[to_match] != timestamp && dfs(to_match))) {
                match[idx] = to;
                match[to] = idx;
                return true;
            }
        }
        return false;
    }
    int bipartite_matching(int ret = 0) {
        for (int i = 0; i < n; i++) if (alive[i]) {
            if (match[i] == -1) ++timestamp, ret += dfs(i);
        }
        return ret;
    }
    friend ostream& operator<<(ostream& os, BipartiteMatching& bm) {
        for (int i = 0; i < bm.n; i++) if (i < bm.match[i]) {
            os << i << " - " << bm.match[i] << endl;
        }
        return os;
    }
};

int gcd(int a, int b) { return b ? gcd(b, a % b) : a; }

int main() {
    int m, n;
    while (cin >> m >> n, m) {
        BipartiteMatching bm(m + n);
        vector<int> left(m), right(n);
        for (int& li: left) cin >> li;
        for (int& ri: right) cin >> ri;
        for (int i = 0; i < m; i++) for (int j = 0; j < n; j++) {
            if (gcd(left[i], right[j]) > 1) bm.add_edge(i, j + m);
        }
        cout << bm.bipartite_matching() << endl;
    }
    return 0;
}
