#include <bits/stdc++.h>
using namespace std;
struct mint {
  static unsigned R, RR, Rinv, W, md, mdninv;
  unsigned val;
  mint() {}
  mint(int a) { val = mulR(a); }
  mint(unsigned a) { val = mulR(a); }
  mint(long long a) { val = mulR(a); }
  mint(unsigned long long a) { val = mulR(a); }
  int get_inv(long long a, int md) {
    long long e, s = md, t = a, u = 1, v = 0;
    while (s) {
      e = t / s;
      t -= e * s;
      u -= e * v;
      swap(t, s);
      swap(u, v);
    }
    if (u < 0) {
      u += md;
    }
    return u;
  }
  void setmod(unsigned m) {
    int i;
    unsigned t;
    W = 32;
    md = m;
    R = (1ULL << W) % md;
    RR = (unsigned long long)R * R % md;
    switch (m) {
      case 104857601:
        Rinv = 2560000;
        mdninv = 104857599;
        break;
      case 998244353:
        Rinv = 232013824;
        mdninv = 998244351;
        break;
      case 1000000007:
        Rinv = 518424770;
        mdninv = 2226617417U;
        break;
      case 1000000009:
        Rinv = 171601999;
        mdninv = 737024967;
        break;
      case 1004535809:
        Rinv = 234947584;
        mdninv = 1004535807;
        break;
      case 1007681537:
        Rinv = 236421376;
        mdninv = 1007681535;
        break;
      case 1012924417:
        Rinv = 238887936;
        mdninv = 1012924415;
        break;
      case 1045430273:
        Rinv = 254466304;
        mdninv = 1045430271;
        break;
      case 1051721729:
        Rinv = 257538304;
        mdninv = 1051721727;
        break;
      default:
        Rinv = get_inv(R, md);
        mdninv = 0;
        t = 0;
        for (i = 0; i < (int)W; i++) {
          if (t % 2 == 0) {
            t += md;
            mdninv |= (1U << i);
          }
          t /= 2;
        }
    }
  }
  unsigned mulR(unsigned a) { return (unsigned long long)a * R % md; }
  unsigned mulR(int a) {
    if (a < 0) {
      a = a % md + md;
    }
    return mulR((unsigned)a);
  }
  unsigned mulR(unsigned long long a) { return mulR((unsigned)(a % md)); }
  unsigned mulR(long long a) {
    a %= md;
    if (a < 0) {
      a += md;
    }
    return mulR((unsigned)a);
  }
  unsigned reduce(unsigned T) {
    unsigned m = T * mdninv,
             t = (unsigned)((T + (unsigned long long)m * md) >> W);
    if (t >= md) {
      t -= md;
    }
    return t;
  }
  unsigned reduce(unsigned long long T) {
    unsigned m = (unsigned)T * mdninv,
             t = (unsigned)((T + (unsigned long long)m * md) >> W);
    if (t >= md) {
      t -= md;
    }
    return t;
  }
  unsigned get() { return reduce(val); }
  mint &operator+=(mint a) {
    val += a.val;
    if (val >= md) {
      val -= md;
    }
    return *this;
  }
  mint &operator-=(mint a) {
    if (val < a.val) {
      val = val + md - a.val;
    } else {
      val -= a.val;
    }
    return *this;
  }
  mint &operator*=(mint a) {
    val = reduce((unsigned long long)val * a.val);
    return *this;
  }
  mint &operator/=(mint a) { return *this *= a.inverse(); }
  mint operator+(mint a) { return mint(*this) += a; }
  mint operator-(mint a) { return mint(*this) -= a; }
  mint operator*(mint a) { return mint(*this) *= a; }
  mint operator/(mint a) { return mint(*this) /= a; }
  mint operator+(int a) { return mint(*this) += mint(a); }
  mint operator-(int a) { return mint(*this) -= mint(a); }
  mint operator*(int a) { return mint(*this) *= mint(a); }
  mint operator/(int a) { return mint(*this) /= mint(a); }
  mint operator+(long long a) { return mint(*this) += mint(a); }
  mint operator-(long long a) { return mint(*this) -= mint(a); }
  mint operator*(long long a) { return mint(*this) *= mint(a); }
  mint operator/(long long a) { return mint(*this) /= mint(a); }
  mint operator-(void) {
    mint res;
    if (val) {
      res.val = md - val;
    } else {
      res.val = 0;
    }
    return res;
  }
  operator bool(void) { return val != 0; }
  operator int(void) { return get(); }
  operator long long(void) { return get(); }
  mint inverse() {
    int a = val, b = md, u = 1, v = 0, t;
    mint res;
    while (b) {
      t = a / b;
      a -= t * b;
      swap(a, b);
      u -= t * v;
      swap(u, v);
    }
    if (u < 0) u += md;
    res.val = (unsigned long long)u * RR % md;
    return res;
  }
  mint pw(unsigned long long b) {
    mint a(*this), res;
    res.val = R;
    while (b) {
      if (b & 1) res *= a;
      b >>= 1;
      a *= a;
    }
    return res;
  }
  bool operator==(int a) { return mulR(a) == val; }
  bool operator!=(int a) { return mulR(a) != val; }
};
unsigned mint::md, mint::W, mint::R, mint::Rinv, mint::mdninv, mint::RR;
mint operator+(int a, mint b) { return mint(a) += b; }
mint operator-(int a, mint b) { return mint(a) -= b; }
mint operator*(int a, mint b) { return mint(a) *= b; }
mint operator/(int a, mint b) { return mint(a) /= b; }
mint operator+(long long a, mint b) { return mint(a) += b; }
mint operator-(long long a, mint b) { return mint(a) -= b; }
mint operator*(long long a, mint b) { return mint(a) *= b; }
mint operator/(long long a, mint b) { return mint(a) /= b; }
inline void rd(int &x) {
  int k, m = 0;
  x = 0;
  for (;;) {
    k = getchar_unlocked();
    if (k == '-') {
      m = 1;
      break;
    }
    if ('0' <= k && k <= '9') {
      x = k - '0';
      break;
    }
  }
  for (;;) {
    k = getchar_unlocked();
    if (k < '0' || k > '9') {
      break;
    }
    x = x * 10 + k - '0';
  }
  if (m) {
    x = -x;
  }
}
inline void wt_L(char a) { putchar_unlocked(a); }
inline void wt_L(int x) {
  char f[10];
  int m = 0, s = 0;
  if (x < 0) {
    m = 1;
    x = -x;
  }
  while (x) {
    f[s++] = x % 10;
    x /= 10;
  }
  if (!s) {
    f[s++] = 0;
  }
  if (m) {
    putchar_unlocked('-');
  }
  while (s--) {
    putchar_unlocked(f[s] + '0');
  }
}
inline void wt_L(mint x) {
  int i;
  i = (int)x;
  wt_L(i);
}
int N;
int M;
int A[100000];
mint dp[100002];
int main() {
  int i, j, k;
  {
    mint x;
    x.setmod(1000000007);
  }
  rd(N);
  rd(M);
  {
    int Lj4PdHRW;
    for (Lj4PdHRW = 0; Lj4PdHRW < M; Lj4PdHRW++) {
      rd(A[Lj4PdHRW]);
    }
  }
  dp[0] = 1;
  k = 0;
  for (i = 0; i < N; i++) {
    if (A[k] == i) {
      k++;
      dp[i] = 0;
    }
    dp[i + 1] += dp[i];
    dp[i + 2] += dp[i];
  }
  wt_L(dp[N]);
  wt_L('\n');
  return 0;
}
