import core.bitop;
import std.algorithm;
import std.ascii;
import std.bigint;
import std.conv;
import std.functional;
import std.math;
import std.numeric;
import std.range;
import std.stdio;
import std.string;
import std.random;
import std.typecons;
import std.container;

alias sread = () => readln.chomp();
alias Point2 = Tuple!(long, "y", long, "x");
long bignum = 1_000_000_007;
auto dp = new long[](100_100);

T lread(T = long)()
{
    return readln.chomp.to!T();
}

T[] aryread(T = long)()
{
    return readln.split.to!(T[])();
}

void scan(TList...)(ref TList Args)
{
    auto line = readln.split();
    foreach (i, T; TList)
    {
        T val = line[i].to!(T);
        Args[i] = val;
    }
}

void main()
{
    long n, m;
    scan(n, m);
    auto denger = new long[](m);
    foreach (ref e; denger)
    {
        e = lread();
    }
    long[] tmp = [0];
    auto need = step(denger ~ tmp, n);
    need.writeln();
}

long step(long[] denger, long n)
{
    ulong j;
    if (denger[j] != 1)
        dp[0] = 1;
    else
        j++;

    if (denger[j] != 2)
        dp[1] = dp[0] + 1;
    else
        j++;

    foreach (i; 2 .. n)
    {
        if (i == denger[j] - 1)
        {
            dp[i] = 0;
            j++;
        }
        else
        {
            dp[i] = (dp[i - 1] + dp[i - 2]) % bignum;
        }
    }
    return dp[n - 1];
}
