#include <bits/stdc++.h>
using namespace std;

template<class T>
bool chmax(T& a, const T& b) {
    if (a < b) { a = b; return true; }
    return false;
}
template<class T>
bool chmin(T& a, const T& b) {
    if (b < a) { a = b; return true; }
    return false;
}

// std::vector Declaration
template<typename T>
vector<T> make_v(size_t a) { return vector<T>(a); }
template<typename T, typename... Ts>
auto make_v(size_t a, Ts... ts) {
    return vector<decltype(make_v<T>(ts...))>(a, make_v<T>(ts...));
}

// std::vector Declaration and Initialization
template<typename T>
vector<T> make_vector(size_t a, T x) { return vector<T>(a, x); }
template<typename T, typename U, typename... Ts>
auto make_vector(size_t a, U b, Ts... ts) {
    return vector<decltype(make_vector<T>(b,ts...))>(a, make_vector<T>(b, ts...));
}

// std::vector Input
template<typename T>
istream& operator>>(istream& is, vector<T>& v) {
    for (auto &e : v) is >> e;
    return is;
}

// std::vector Debug
template<typename T>
ostream& operator<<(ostream& os, const vector<T>& v) {
    os << "[";
    bool a = 1;
    for (auto e : v) {
        os << (a ? "" : " ");
        os << e;
        a = 0;
    }
    os << "]";
    return os;
}

// std::array Debug
template<typename T, size_t n>
ostream& operator<<(ostream& os, const array<T, n>& v) {
    os << "[";
    bool a = 1;
    for (auto e : v) {
        os << (a ? "" : " ");
        os << e;
        a = 0;
    }
    os << "]";
    return os;
}

// std::deque Debug
template<typename T>
ostream& operator<<(ostream& os, const deque<T>& d) {
    os << "[";
    bool a = 1;
    for (auto e : d) {
        os << (a ? "" : " ");
        os << e;
        a = 0;
    }
    os << "]";
    return os;
}

// std::pair Debug
template<typename T, typename U>
ostream& operator<<(ostream& os, const pair<T, U>& p) {
    os << "(" << p.first << " " << p.second << ")";
    return os;
}

// std::set Debug
template<typename T>
ostream& operator<<(ostream& os, const set<T>& st) {
    os << "{";
    bool a = 1;
    for (auto e : st) {
        os << (a ? "" : " ");
        os << e;
        a = 0;
    }
    os << "}";
    return os;
}

// std::multiset Debug
template<typename T>
ostream& operator<<(ostream& os, const multiset<T>& st) {
    os << "{";
    bool a = 1;
    for (auto e : st) {
        os << (a ? "" : " ");
        os << e;
        a = 0;
    }
    os << "}";
    return os;
}

// std::map Debug
template<typename T, typename U>
ostream& operator<<(ostream& os, const map<T, U>& mp) {
    os << "{";
    bool a = 1;
    for (auto e : mp) {
        os << (a ? "" : " ");
        os << e.first << ":" << e.second;
        a = 0;
    }
    os << "}";
    return os;
}

// std::tuple Debug
template<int N, class Tuple>
void out(ostream& os, const Tuple& t){}
template<int N, class Tuple, class H, class ...Ts>
void out(ostream& os, const Tuple& t) {
    if (N) os << " ";
    os << get<N>(t);
    out<N+1,Tuple,Ts...>(os, t);
}
template<class ...Ts>
ostream& operator<<(ostream& os, const tuple<Ts...>& t) {
    os << "(";
    out<0,tuple<Ts...>,Ts...>(os, t);
    os << ")";
    return os;
}

// Debug
#define DUMP(x) cerr<<#x<<" = "<<(x)<<endl

// Weighted edge
template<typename T>
struct edge {
    int src, to;
    T cost;

    edge() {}
    edge(int to, T cost) : src(-1), to(to), cost(cost) {}
    edge(int src, int to, T cost) : src(src), to(to), cost(cost) {}

    friend ostream& operator<<(ostream& os, const edge& e) {
        return os << "(" << e.src << "->" << e.to << ":" << e.cost << ")";
    }
};

using LL = int64_t;

#define fs first
#define sc second

const int64_t MOD = 1e9+7;


template<typename T>
struct FordFulkerson {
    struct edge {
        int to, rev;
        T cap;
        edge(int to, T cap, int rev) :
            to(to), cap(cap), rev(rev) {}
    };

    vector<vector<edge>> g;
    vector<int> used;
    const T INF;
    int timestamp;

    FordFulkerson(int n) :
        INF(numeric_limits<T>::max()),
        timestamp(0), g(n), used(n, -1) {}

    void add_edge(int s, int t, T cap) {
        g[s].emplace_back(t, cap, (int)g[t].size());
        g[t].emplace_back(s,   0, (int)g[s].size() - 1);
    }

    T dfs(int v, const int t, T flow) {
        if (v == t) return flow;
        used[v] = timestamp;
        for (edge &e : g[v]) {
            if (e.cap > 0 and used[e.to] != timestamp) {
                T d = dfs(e.to, t, min(flow, e.cap));
                if (d > 0) {
                    e.cap -= d;
                    g[e.to][e.rev].cap += d;
                    return d;
                }
            }
        }
        return 0;
    }

    T max_flow(int s, int t) {
        T flow = 0;
        for(T f; (f = dfs(s, t, INF)) > 0; timestamp++) {
            flow += f;
        }
        return flow;
    }
};

template<typename T>
struct Dinic {
    // O(EV^2)
    struct edge {
        int to, rev;
        T cap;
        edge(int to, T cap, int rev) :
            to(to), cap(cap), rev(rev) {}
    };

    vector<vector<edge>> g;
    vector<int> level, iter;
    const T INF;

    Dinic(int V) : INF(numeric_limits<T>::max()), g(V) {}

    void add_edge(int s, int t, T cap) {
        g[s].emplace_back(t, cap, (int)g[t].size());
        g[t].emplace_back(s,   0, (int)g[s].size() - 1);
    }

    bool bfs(int s, int t) {
        level.assign(g.size(), -1);
        queue<int> que;
        level[s] = 0;
        que.push(s);
        while (!que.empty()) {
            int v = que.front();
            que.pop();
            for (auto &e : g[v]) {
                if (e.cap > 0 && level[e.to] == -1) {
                    level[e.to] = level[v] + 1;
                    que.push(e.to);
                }
            }
        }
        return level[t] != -1;
    }

    T dfs(int v, const int t, T flow) {
        if (v == t) return flow;
        for (int &i = iter[v]; i < g[v].size(); i++) {
            edge &e = g[v][i];
            if (e.cap > 0 && level[v] < level[e.to]) {
                T d = dfs(e.to, t, min(flow, e.cap));
                if (d > 0) {
                    e.cap -= d;
                    g[e.to][e.rev].cap += d;
                    return d;
                }
            }
        }
        return 0;
    }

    T max_flow(int s, int t) {
        T flow = 0;
        while (bfs(s, t)) {
            iter.assign(g.size(), 0);
            T f = 0;
            while((f = dfs(s, t, INF)) > 0) flow += f;
        }
        return flow;
    }
};


int main()
{
    cin.tie(0);
    ios::sync_with_stdio(false);
    cout << fixed << setprecision(10);

    while (true) {
        int m, n;
        cin >> m >> n;
        if (m == 0) break;
        vector<int> b(m), r(n); cin >> b >> r;

        Dinic<int> g(m+n+2);
        for (int i = 0; i < m; ++i) {
            g.add_edge(m+n, i, 1);
        }
        for (int i = 0; i < n; ++i) {
            g.add_edge(i+m, m+n+1, 1);
        }
        for (int i = 0; i < m; ++i) {
            for (int j = 0; j < n; ++j) {
                if (__gcd(b[i], r[j]) != 1) {
                    g.add_edge(i, j+m, 1);
                }
            }
        }

        cout << g.max_flow(m+n, m+n+1) << endl;
    }

    return 0;
}



Measured memory_bytes: 7372