#include <vector>
#include <list>
#include <map>
#include <set>
#include <unordered_set>
#include <unordered_map>
#include <deque>
#include <stack>
#include <bitset>
#include <algorithm>
#include <functional>
#include <numeric>
#include <utility>
#include <sstream>
#include <queue>
#include <iostream>
#include <iomanip>
#include <cstdio>
#include <cmath>
#include <cstdlib>
#include <cctype>
#include <string>
#include <cstring>
#include <ctime>
#include <fstream>
#include <cstdio>
#include <climits>
#include <complex>
#include <cstdint>
#include <tuple>

#define M_PI       3.14159265358979323846

using namespace std;

//conversion
//------------------------------------------
inline int toInt(string s) { int v; istringstream sin(s); sin >> v; return v; }
template<class T> inline string toString(T x) { ostringstream sout; sout << x; return sout.str(); }
inline int readInt() { int x; scanf("%d", &x); return x; }

//typedef
//------------------------------------------
typedef vector<int> VI;
typedef vector<VI> VVI;
typedef vector<string> VS;
typedef pair<int, int> PII;
typedef pair<int, PII> TIII;
typedef long long LL;
typedef unsigned long long ULL;
typedef vector<LL> VLL;
typedef vector<VLL> VVLL;

//container util

//------------------------------------------
#define ALL(a)  (a).begin(),(a).end()
#define RALL(a) (a).rbegin(), (a).rend()
#define PB push_back
#define MP make_pair
#define SZ(a) int((a).size())
#define SQ(a) ((a)*(a))
#define EACH(i,c) for(typeof((c).begin()) i=(c).begin(); i!=(c).end(); ++i)
#define EXIST(s,e) ((s).find(e)!=(s).end())
#define SORT(c) sort((c).begin(),(c).end())

//repetition
//------------------------------------------
#define FOR(i,s,n) for(int i=s;i<(int)n;++i)
#define REP(i,n) FOR(i,0,n)
#define MOD 1000000007

#define rep(i, a, b) for(int i = a; i < (b); ++i)
#define trav(a, x) for(auto& a : x)
#define all(x) x.begin(), x.end()
#define sz(x) (int)(x).size()
struct Edge {
    int to, cost;
    Edge(int to, int cost): to(to), cost(cost) {}
};

typedef long long ll;
typedef pair<int, int> pii;
typedef vector<int> vi;
typedef vector<vector<Edge>> AdjList;
AdjList graph;

const int INF = 100000000;



int GCD(int a, int b){
    if(a < b) swap(a, b);
    if(b == 0) return a;
    return GCD(b, a%b);
}

int N, K;
bool can[510][510];
struct edge{ int to, cap, rev;};
vector<edge> G[1010];
bool used[1010];

void add_edge(int from, int to, int cap){
    G[from].push_back((edge){to, cap, (int)G[to].size() });
    G[to].push_back((edge){from, 0, (int)G[from].size()-1}) ;
}

int dfs(int v, int t, int f) {
    if(v == t) return f;
    used[v] = true;

    for(int i=0; i<G[v].size(); ++i){
        edge &e = G[v][i];
        if(!used[e.to] && e.cap > 0){
            int d = dfs(e.to, t, min(f, e.cap));
            if( d > 0){
                e.cap -= d;
                G[e.to][e.rev].cap += d;
                return d;
            }
        }
    }
    return 0;
}
int max_flow(int s, int t){
    int flow = 0;
    for(;;){
        memset(used, 0, sizeof(used));
        int f = dfs(s, t, INF);
        if( f == 0) return flow;
        flow += f;
    }
}


int main() {
    //cout << fixed << setprecision(15);
   
    int m, n;
    while(cin >> m >> n){
        if(m == 0 && n==0) break;
        for(int i=0; i<1010; ++i) G[i].clear();
        int s = m + n, t = s+1;

        for(int i=0; i<m; ++i){
            add_edge(s, i, 1);
        }
        for(int i=0; i<n; ++i){
            add_edge(m+i, t, 1);
        }

        vector<int> r, b;
        for(int i=0; i<m; ++i){
            int a = readInt();
            b.push_back(a);
        }
        for(int i=0; i<n; ++i){
            int a = readInt();
            r.push_back(a);
        }
        for(int i=0; i<m; ++i){
            for(int j=0; j<n; ++j){
                int d = GCD(b[i], r[j]);
                if(d > 1) add_edge(i, m+j, 1);
            }
        }

        cout << max_flow(s, t) << endl;
    }
    return 0;
}


Measured memory_bytes: 9456