//#define _GLIBCXX_DEBUG
#include <bits/stdc++.h>

using namespace std;

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

#define mk make_pair
#define inb push_back
#define X first
#define Y second
#define all(v) v.begin(), v.end()
#define sqr(x) (x) * (x)

/** Fast input-output */

template <class T = int> inline T readInt();
inline double readDouble();
inline int readUInt();
inline int readChar(); // first non-blank character
inline void readWord( char *s );
inline bool readLine( char *s ); // do not save '\n'
inline bool isEof();
inline int getChar();
inline int peekChar();
inline bool seekEof();
inline void skipBlanks();

template <class T> inline void writeInt( T x, char end = 0, int len = -1 );
inline void writeChar( int x );
inline void writeWord( const char *s );
inline void writeDouble( double x, int len = 0 );
inline void flush();

static struct buffer_flusher_t {
    ~buffer_flusher_t() {
        flush();
    }
} buffer_flusher;

/** Read */

static const int buf_size = 4096;

static unsigned char buf[buf_size];
static int buf_len = 0, buf_pos = 0;

inline bool isEof() {
    if (buf_pos == buf_len) {
        buf_pos = 0, buf_len = fread(buf, 1, buf_size, stdin);
        if (buf_pos == buf_len)
            return 1;
    }
    return 0;
}

inline int getChar() {
    return isEof() ? -1 : buf[buf_pos++];
}

inline int peekChar() {
    return isEof() ? -1 : buf[buf_pos];
}

inline bool seekEof() {
    int c;
    while ((c = peekChar()) != -1 && c <= 32)
        buf_pos++;
    return c == -1;
}

inline void skipBlanks() {
    while (!isEof() && buf[buf_pos] <= 32U)
        buf_pos++;
}

inline int readChar() {
    int c = getChar();
    while (c != -1 && c <= 32)
        c = getChar();
    return c;
}

inline int readUInt() {
    int c = readChar(), x = 0;
    while ('0' <= c && c <= '9')
        x = x * 10 + c - '0', c = getChar();
    return x;
}

template <class T>
inline T readInt() {
    int s = 1, c = readChar();
    T x = 0;
    if (c == '-')
        s = -1, c = getChar();
    else if (c == '+')
        c = getChar();
    while ('0' <= c && c <= '9')
        x = x * 10 + c - '0', c = getChar();
    return s == 1 ? x : -x;
}

inline double readDouble() {
    int s = 1, c = readChar();
    double x = 0;
    if (c == '-')
        s = -1, c = getChar();
    while ('0' <= c && c <= '9')
        x = x * 10 + c - '0', c = getChar();
    if (c == '.') {
        c = getChar();
        double coef = 1;
        while ('0' <= c && c <= '9')
            x += (c - '0') * (coef *= 1e-1), c = getChar();
    }
    return s == 1 ? x : -x;
}

inline void readWord( char *s ) {
    int c = readChar();
    while (c > 32)
        *s++ = c, c = getChar();
    *s = 0;
}

inline bool readLine( char *s ) {
    int c = getChar();
    while (c != '\n' && c != -1)
        *s++ = c, c = getChar();
    *s = 0;
    return c != -1;
}

/** Write */

static int write_buf_pos = 0;
static char write_buf[buf_size];

inline void writeChar( int x ) {
    if (write_buf_pos == buf_size)
        fwrite(write_buf, 1, buf_size, stdout), write_buf_pos = 0;
    write_buf[write_buf_pos++] = x;
}

inline void flush() {
    if (write_buf_pos)
        fwrite(write_buf, 1, write_buf_pos, stdout), write_buf_pos = 0;
}

template <class T>
inline void writeInt( T x, char end, int output_len ) {
    if (x < 0)
        writeChar('-'), x = -x;

    char s[24];
    int n = 0;
    while (x || !n)
        s[n++] = '0' + x % 10, x /= 10;
    while (n < output_len)
        s[n++] = '0';
    while (n--)
        writeChar(s[n]);
    if (end)
        writeChar(end);
}

inline void writeWord( const char *s ) {
    while (*s)
        writeChar(*s++);
}

inline void writeDouble( double x, int output_len ) {
    if (x < 0)
        writeChar('-'), x = -x;
    int t = (int)x;
    writeInt(t), x -= t;
    writeChar('.');
    for (int i = output_len - 1; i > 0; i--) {
        x *= 10;
        t = std::min(9, (int)x);
        writeChar('0' + t), x -= t;
    }
    x *= 10;
    t = std::min(9, (int)(x + 0.5));
    writeChar('0' + t);
}


int solve();

int main()
{
    //ios_base::sync_with_stdio(0);
    //cin.tie(0);
#define TASK "carno"
#ifndef _DEBUG
    //freopen(TASK".in", "r", stdin), freopen(TASK".out", "w", stdout);
#endif
    solve();
}

const int K = 322;

struct SqrtDecomposition
{
    vector<vector<int>> bl;
    set<int> ok;
    SqrtDecomposition(int n)
    {
        for (int i = 0, idb = 0; i < n; i += K, ++idb)
        {
            bl.inb({});
            for (int j = 0; i + j < min(i + K, n); ++j)
            {
                ok.insert(i + j);
                bl[idb].inb(0);
            }
        }
    };
    pii get_block(int x)
    {
        int idb = 0;
        for (auto &v : bl)
        {
            if (x >= (int)v.size())
            {
                x -= (int)v.size();
            }
            else
            {
                break;
            }
            ++idb;
        }
        return mk(idb, x);
    }
    void trykill(int idl)
    {
        if (!bl[idl].empty() || bl.size() == 1)
            return;
        bl.erase(bl.begin() + idl);
    }
    void balance(int idl)
    {
        if (bl[idl].size() < 2 * K)
            return;
        vi nbl;
        int sz = bl[idl].size();
        while ((int)bl[idl].size() >= sz / 2)
        {
            nbl.inb(bl[idl].back());
            bl[idl].pop_back();
        }
        reverse(all(nbl));
        bl.insert(bl.begin() + idl + 1, nbl);
    }
    void insert(int pos, int x)
    {
        pii res = get_block(pos);
        int l = res.X;
        int id = max(res.Y, 0);
        int nxt0 = *ok.lower_bound(pos);
        if (bl[l][id])
        {
            del(nxt0);
            bl[l].insert(bl[l].begin() + id, x);
        }
        else
        {
            bl[l][id] = x;
        }
        ok.erase(nxt0);
        balance(l);
    }
    void del(int pos)
    {
        pii res = get_block(pos);
        int l = res.X;
        int id = res.Y;
        bl[l].erase(bl[l].begin() + id);
        trykill(l);
    }
    void collect(vector<int>& ans)
    {
        ans.clear();
        for (auto &v : bl)
        {
            for (auto &x : v)
            {
                ans.inb(x);
            }
        }
        while (!ans.back())
            ans.pop_back();
    }
};

int solve()
{
    int n = readInt(), m = readInt();
    SqrtDecomposition T = SqrtDecomposition(n + m);
    auto printans = [&]()
    {
        vi ans;
        T.collect(ans);
        printf("%d\n", (int)ans.size());
        for (int x : ans)
            printf("%d ", x);
        puts("");
    };
    for (int i = 1; i <= n; ++i)
    {
        T.insert(readInt() - 1, i);
    }
    printans();
    return 0;
}