#include <algorithm>
#include <cmath>
#include <climits>
#include <cstdio>
#include <cstdlib>
#include <cstring>
#include <fstream>
#include <iostream>
#include <list>
#include <map>
#include <queue>
#include <set>
#include <sstream>
#include <stack>
#include <string>
#include <vector>
#include <cassert>
#include <functional>

using namespace std;

#define LOG(...) printf(__VA_ARGS__)
//#define LOG(...)
#define FOR(i,a,b) for(int i=(int)(a);i<(int)(b);++i)
#define REP(i,n) for(int i=0;i<(int)(n);++i)
#define ALL(a) (a).begin(),(a).end()
#define RALL(a) (a).rbegin(),(a).rend()
#define EXIST(s,e) ((s).find(e)!=(s).end())
#define SORT(c) sort((c).begin(),(c).end())
#define RSORT(c) sort((c).rbegin(),(c).rend())
#define CLR(a) memset((a), 0 ,sizeof(a))

typedef long long ll;
typedef unsigned long long ull;
typedef vector<bool> vb;
typedef vector<int> vi;
typedef vector<ll> vll;
typedef vector<vb> vvb;
typedef vector<vi> vvi;
typedef vector<vll> vvll;
typedef pair<int, int> pii;
typedef pair<ll, ll> pll;

const int dx[] = { -1, 0, 1, 0 }; const int dy[] = { 0, 1, 0, -1 };

struct UnionFind {
	vector<int> v;
	UnionFind(int n) : v(n) { for (int i = 0; i < n; i++) v[i] = i; }
	int  find(int x) { return v[x] == x ? x : v[x] = find(v[x]); }
	void unite(int x, int y) { v[find(x)] = find(y); }
};
int gcd(int a, int b) {
	if (a < b) {
		swap(a, b);
	}
	while (b != 0) {
		a = a%b;
		swap(a, b);
	}
	return a;
}
int main() {
	int blue_size, red_size;
	while (cin >> blue_size >> red_size, red_size) {
		vector<int> blue(blue_size);
		REP(i, blue_size)
			cin >> blue[i];
		vector<int> red(red_size);
		REP(i, red_size)
			cin >> red[i];
		SORT(blue);
		SORT(red);
		vb blueu(blue.size(), false);
		vb redu(red.size(), false);
		vvi bluec(blue.size());
		vvi redc(red.size());
		set<pii> connect;//blue red
		REP(i, blue.size()) {
			REP(j, red.size()) {
				if (gcd(blue[i], red[j]) != 1) {
					bluec[i].push_back(j);
					redc[j].push_back(i);
					if (!blueu[i] && !redu[j]) {
						blueu[i] = true;
						redu[j] = true;
						connect.insert({ i,j });
					}
				}
			}
		}
		REP(i, blue.size()) {
			if (!blueu[i]) {
				stack<pii> route;
				route.push({ i,0 });
				vb bluev(blue.size(), false);
				vb redv(red.size(), false);
				bluev[i] = true;
				while (!route.empty()) {
wf:
					pii st = route.top();
					if (st.second == 1 && !redu[st.first]) {
						redu[st.first] = true;
						while (route.size() > 1) {
							if (route.size() % 2 == 0) {
								pii st2 = route.top();
								route.pop();
								connect.insert({ route.top().first,st2.first });
							}
							else {
								pii st2 = route.top();
								route.pop();
								connect.erase({ st2.first,route.top().first });
							}
						}
						blueu[i] = true;
						break;
					}
					if (st.second == 0) {
						REP(j, bluec[st.first].size()) {
							if (!redv[bluec[st.first][j]] && connect.find({st.first,bluec[st.first][j] })==connect.end()) {
								redv[bluec[st.first][j]] = true;
								route.push({ bluec[st.first][j],1});
								goto wf;
							}
						}
					}
					else {
						REP(j, redc[st.first].size()) {
							if (!bluev[redc[st.first][j]] && connect.find({ redc[st.first][j],st.first }) != connect.end()) {
								bluev[redc[st.first][j]] = true;
								route.push({ redc[st.first][j],0 });
								goto wf;
							}
						}
					}
					route.pop();
				}
			}
		}
		cout << connect.size() << endl;
	}
}

Measured memory_bytes: 4532