#include <bits/stdc++.h>
using namespace std;
#define Buildup() ios::sync_with_stdio(false),cin.tie(nullptr)

#define make_unique(x) (x).resize(unique(all((x)))-(x).begin())
#define rotate(x,k) rotate(x.begin(),x.begin()+k,x.end());
#define all(x) (x).begin(),(x).end()
#define allr(x) (x).rbegin(),(x).rend()
#define ceil(x,y) (x+y-1)/(y)
#define sz(x) (int)(x).size()
#define PI 3.141592653589793238
#define ld long double
#define ull unsigned long long
#define ll long long
#define nl '\n'
#define ff first
#define ss second
#define IM INT_MAX
#define IN INT_MIN
#define LM LLONG_MAX
#define LN LLONG_MIN
#define pb push_back
#define pp pop_back
#define ins insert
#define lb lower_bound
#define ub upper_bound

#define Nl '\n'
#define itn int

// const int M = 998244353;
const int M = 1e9+7;
// const int N = 2e5+5;
// const int N = 1e5+5;

constexpr int inf = 1E9;

#ifndef ONLINE_JUDGE
#define dbg(x...) cerr << #x << " : ["; _print(x)
#else
#define dbg(x...)
#endif

void __print(int x) {cerr << x;}
void __print(long x) {cerr << x;}
void __print(ll x) {cerr << x;}
void __print(ull x) {cerr << x;}
void __print(ld x) {cerr << x;}
void __print(float x) {cerr << x;}
void __print(double x) {cerr << x;}
void __print(char x) {cerr << '\'' << x << '\'';}
void __print(const char *x) {cerr << '\"' << x << '\"';}
void __print(const string &x) {cerr << '\"' << x << '\"';}
void __print(bool x) {cerr << (x ? "T" : "F");}

template<typename T, typename V>
void __print(const pair<T, V> &x) {cerr << '{'; __print(x.ff); cerr << ','; __print(x.ss); cerr << '}';}
template<typename T>
void __print(const T &x) {int f = 0; cerr << '{'; for (auto &i: x) cerr << (f++ ? "," : ""), __print(i); cerr << "}";}
void _print() {cerr << "]\n";}
void __print(vector<bool> &v) {int f = 0; cerr << '{'; for (auto &&i : v) cerr << (f++ ? "," : "") << (i ? "T" : "F"); cerr << "}";}
template <typename T, typename... V>
void _print(T t, V... v) {__print(t); if (sizeof...(v)) cerr << ", "; _print(v...);}
template <size_t N> void __print(bitset<N> x) {cerr << x;}


/* .....!! Start by doing what's necessary; then do what's possible;
                            and suddenly you are doing impossible !!..... */

int main(){
    #ifndef ONLINE_JUDGE
        freopen("errorf.in", "w", stderr);
    #endif

    Buildup();

        int ___ = 1;
        // cin >> ___;

        while(___--){

            int n,m;
            cin>>n>>m;

            vector<int> v(n);
            for(auto &it : v) cin>>it;

            vector<int> dp(m+2);
            for(int i=0; i<n; i++){
                auto ndp = dp;
                for(int j=1; j<=m; j++){
                    if(!i){
                        if(!v[i]){
                            ndp.assign(m+2,1);
                            ndp.front() = ndp.back() = 0;
                        }
                        else ndp[v[i]] = 1;
                    }
                    else if(v[i]){
                        ndp.assign(m+2,0);
                        (ndp[v[i]] += dp[v[i]-1]) %= M;
                        (ndp[v[i]] += dp[v[i]]) %= M;
                        (ndp[v[i]] += dp[v[i]+1]) %= M;
                    }
                    else{
                        (ndp[j] += dp[j-1]) %= M;
                        (ndp[j] += dp[j]) %= M;
                        (ndp[j] += dp[j+1]) %= M;
                    }
                }
                dp = ndp;
            }

            for(int i=1; i<=m; i++) (dp[i] += dp[i-1]) %= M;
            cout<<dp[m]<<nl;
            // int ans = 0;
            // for(auto &x : dp) (ans += x) %= M;
            // dbg(dp);

        }

}