#include<bits/stdc++.h>

#define LL long long

#define fi first

#define se second

#define mk make_pair

#define PLL pair<LL, LL>

#define PLI pair<LL, int>

#define PII pair<int, int>

#define SZ(x) ((int)x.size())

#define ull unsigned long long

using namespace std;

const int N = 2e5 + ;

const int inf = 0x3f3f3f3f;

const LL INF = 0x3f3f3f3f3f3f3f3f;

const int mod = 1e9 + ;

const double eps = 1e-;

const double PI = acos(-);

LL n, m, dp[N], path[N];

bool ban[N];

vector<LL> gg[N];

vector<LL> ans;

vector<LL> vc;

LL x, y;

LL exgcd(LL a, LL b, LL &x, LL &y) {

    if(!b) {

        x = ; y = ;

        return a;

    } else {

        LL gcd, t; gcd = exgcd(b, a % b, x, y);

        t = x; x = y; y = t - (a / b) * y;

        return gcd;

    }

}

LL dfs(LL x) {

    if(~dp[x]) return dp[x];

    dp[x] = ;

    for(int i =  * x; i < m; i += x) {

        LL cnt = dfs(i);

        if(cnt > dp[x]) {

            dp[x] = cnt;

            path[x] = i;

        }

    }

    dp[x] += SZ(gg[x]);

    return dp[x];

}

LL solve(LL pre, LL to) {

    if(pre == -) ans.push_back(to);

    else {

        LL gcd = exgcd(pre, -m, x, y);

        if(to % gcd) exit();

        x *= to / gcd; y *= to / gcd;

        LL mo = abs(m / gcd);

        x = ((x % mo) + mo) % mo;

        ans.push_back(x);

    }

    return to;

}

int main() {

    memset(dp, -, sizeof(dp));

    scanf("%lld%lld", &n, &m);

    for(int i = ; i <= n; i++) {

        int x; scanf("%d", &x);

        ban[x] = true;

    }

    for(LL i = ; i < m; i++) {

        if(ban[i]) continue;

        gg[__gcd(i, m)].push_back(i);

    }

    dfs();

    LL pre = -;

    for(LL gcd = ; gcd; gcd = path[gcd]) {

        for(int i = ; i < SZ(gg[gcd]); i++)

            pre = solve(pre, gg[gcd][i]);

    }

    if(!ban[]) ans.push_back();

    printf("%d\n", SZ(ans));

    for(auto& t : ans) printf("%lld ", t);

    puts("");

    return ;

}

/*

*/