import java.util.*;

class Main{
  public static void main(String args[]){
    Scanner sc = new Scanner(System.in);
    final int modder=1000000007;
    int n=sc.nextInt();
    int m=sc.nextInt();
    int dp[]=new int[n+1];
    Arrays.fill(dp,0);
    for(int i=0;i<m;i++){
      dp[sc.nextInt()]=-1;
    }
    dp[0]=1;
    dp[1]=dp[1]==-1?0:1;
    for(int i=2;i<=n;i++){
      if(dp[i]!=-1){
        dp[i]=(dp[i-1]+dp[i-2])%modder;
      }else{
        dp[i]=0;
      }
    }
    System.out.println(dp[n]);
  }
} import java.util.*; util.* java class Main{
  public static void main(String args[]){
    Scanner sc = new Scanner(System.in);
    final int modder=1000000007;
    int n=sc.nextInt();
    int m=sc.nextInt();
    int dp[]=new int[n+1];
    Arrays.fill(dp,0);
    for(int i=0;i<m;i++){
      dp[sc.nextInt()]=-1;
    }
    dp[0]=1;
    dp[1]=dp[1]==-1?0:1;
    for(int i=2;i<=n;i++){
      if(dp[i]!=-1){
        dp[i]=(dp[i-1]+dp[i-2])%modder;
      }else{
        dp[i]=0;
      }
    }
    System.out.println(dp[n]);
  }
} Main public static void main(String args[]){
    Scanner sc = new Scanner(System.in);
    final int modder=1000000007;
    int n=sc.nextInt();
    int m=sc.nextInt();
    int dp[]=new int[n+1];
    Arrays.fill(dp,0);
    for(int i=0;i<m;i++){
      dp[sc.nextInt()]=-1;
    }
    dp[0]=1;
    dp[1]=dp[1]==-1?0:1;
    for(int i=2;i<=n;i++){
      if(dp[i]!=-1){
        dp[i]=(dp[i-1]+dp[i-2])%modder;
      }else{
        dp[i]=0;
      }
    }
    System.out.println(dp[n]);
  } main {
    Scanner sc = new Scanner(System.in);
    final int modder=1000000007;
    int n=sc.nextInt();
    int m=sc.nextInt();
    int dp[]=new int[n+1];
    Arrays.fill(dp,0);
    for(int i=0;i<m;i++){
      dp[sc.nextInt()]=-1;
    }
    dp[0]=1;
    dp[1]=dp[1]==-1?0:1;
    for(int i=2;i<=n;i++){
      if(dp[i]!=-1){
        dp[i]=(dp[i-1]+dp[i-2])%modder;
      }else{
        dp[i]=0;
      }
    }
    System.out.println(dp[n]);
  } Scanner sc = new Scanner(System.in); sc new Scanner(System.in) final int modder=1000000007; modder 1000000007 int n=sc.nextInt(); n sc.nextInt() sc.nextInt sc int m=sc.nextInt(); m sc.nextInt() sc.nextInt sc int dp[]=new int[n+1]; dp new int[n+1] n+1 n 1 Arrays.fill(dp,0) Arrays.fill Arrays dp 0 for(int i=0;i<m;i++){
      dp[sc.nextInt()]=-1;
    } int i=0; int i=0; i 0 i<m i m i++ i++ i {
      dp[sc.nextInt()]=-1;
    } {
      dp[sc.nextInt()]=-1;
    } dp[sc.nextInt()]=-1 dp[sc.nextInt()] dp sc.nextInt() sc.nextInt sc -1 1 dp[0]=1 dp[0] dp 0 1 dp[1]=dp[1]==-1?0:1 dp[1] dp 1 dp[1]==-1?0:1 dp[1]==-1 dp[1] dp 1 -1 1 0 1 for(int i=2;i<=n;i++){
      if(dp[i]!=-1){
        dp[i]=(dp[i-1]+dp[i-2])%modder;
      }else{
        dp[i]=0;
      }
    } int i=2; int i=2; i 2 i<=n i n i++ i++ i {
      if(dp[i]!=-1){
        dp[i]=(dp[i-1]+dp[i-2])%modder;
      }else{
        dp[i]=0;
      }
    } {
      if(dp[i]!=-1){
        dp[i]=(dp[i-1]+dp[i-2])%modder;
      }else{
        dp[i]=0;
      }
    } if(dp[i]!=-1){
        dp[i]=(dp[i-1]+dp[i-2])%modder;
      }else{
        dp[i]=0;
      } dp[i]!=-1 dp[i] dp i -1 1 {
        dp[i]=(dp[i-1]+dp[i-2])%modder;
      } dp[i]=(dp[i-1]+dp[i-2])%modder dp[i] dp i (dp[i-1]+dp[i-2])%modder (dp[i-1]+dp[i-2]) dp[i-1] dp i-1 i 1 dp[i-2] dp i-2 i 2 modder {
        dp[i]=0;
      } dp[i]=0 dp[i] dp i 0 System.out.println(dp[n]) System.out.println System.out System System.out dp[n] dp n String args[] args
import java.util.*;

class Main{
  public static void main(String args[]){
    Scanner sc = new Scanner(System.in);
    final int modder=1000000007;
    int n=sc.nextInt();
    int m=sc.nextInt();
    int dp[]=new int[n+1];
    Arrays.fill(dp,0);
    for(int i=0;i<m;i++){
      dp[sc.nextInt()]=-1;
    }
    dp[0]=1;
    dp[1]=dp[1]==-1?0:1;
    for(int i=2;i<=n;i++){
      if(dp[i]!=-1){
        dp[i]=(dp[i-1]+dp[i-2])%modder;
      }else{
        dp[i]=0;
      }
    }
    System.out.println(dp[n]);
  }
}
