#include <bits/stdc++.h>
using namespace std;
#define mp make_pair
#define pb push_back
typedef long long int LLI;
typedef vector<int> vi;
typedef pair<int,int> pii;
#define MOD 1000000007
#define MOD2 998244353

int power[1001000],power2[1001000];
int a[300000];
vi vv[300001];
bitset<1001000> bs;
int getAll(int l,int r) {
    if (l == r) {
        vv[r+1].pb(l);
        return 0;
    }

    int i,mid = (l+r) / 2;
    getAll(l,mid),getAll(mid+1,r);
    vi all;
    int mx = 0;
    int sum1 = 0,sum2 = 0;
    map<pii,int> M1,M2;
    for (i = mid; i >= l; i--) {
        int u = a[i];
        while (bs[u]) bs[u] = 0,u++;
        bs[u] = 1,all.pb(u),mx = max(mx,u);
        sum1 += power[a[i]],sum1 %= MOD;
        sum2 += power2[a[i]],sum2 %= MOD2;
        int h1 = (power[mx+1]-sum1+MOD) % MOD;
        int h2 = (power2[mx+1]-sum2+MOD2) % MOD2;
        M1[mp(h1,h2)] = i;
    }
    sum1 = sum2 = 0;
    for (i = mid+1; i <= r; i++) {
        sum1 += power[a[i]],sum1 %= MOD;
        sum2 += power2[a[i]],sum2 %= MOD2;
        if (M1.count(mp(sum1,sum2))) vv[i+1].pb(M1[mp(sum1,sum2)]);
    }
    for (int u: all) bs[u] = 0;
    all.clear();
    mx = 0,sum1 = 0,sum2 = 0;
    for (i = mid+1; i <= r; i++) {
        int u = a[i];
        while (bs[u]) bs[u] = 0,u++;
        bs[u] = 1,all.pb(u),mx = max(mx,u);
        sum1 += power[a[i]],sum1 %= MOD;
        sum2 += power2[a[i]],sum2 %= MOD2;
        int h1 = (power[mx+1]-sum1+MOD) % MOD;
        int h2 = (power2[mx+1]-sum2+MOD2) % MOD2;
        M2[mp(h1,h2)] = i;
    }
    sum1 = sum2 = 0;
    for (i = mid; i >= l; i--) {
        sum1 += power[a[i]],sum1 %= MOD;
        sum2 += power2[a[i]],sum2 %= MOD2;
        if (M2.count(mp(sum1,sum2))) vv[M2[mp(sum1,sum2)]+1].pb(i);
    }
    for (int u: all) bs[u] = 0;
    all.clear();
    return 0;
}
int dp[300001];
int main() {
    int i;
    power[0] = power2[0] = 1;
    for (i = 1; i < 1001000; i++) {
        power[i] = (2*power[i-1]) % MOD;
        power2[i] = (2*power2[i-1]) % MOD2;
    }
    int n;
    scanf("%d",&n);
    for (i = 0; i < n; i++) scanf("%d",&a[i]);

    dp[0] = 1;
    getAll(0,n-1);
    for (i = 0; i < n; i++) {
        sort(vv[i+1].begin(),vv[i+1].end());
        vv[i+1].resize(unique(vv[i+1].begin(),vv[i+1].end())-vv[i+1].begin());
        for (int u: vv[i+1]) {
            dp[i+1] += dp[u];
            if (dp[i+1] >= MOD) dp[i+1] -= MOD;
        }
    }
    printf("%d\n",dp[n]);

    return 0;
}