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#include<cstdio>
#include<iostream>
#include<algorithm>
#include<string>
#include<vector>
#include<map>

using namespace std;

typedef vector<int> VI;
typedef vector<vector<int> > VVI;
typedef long long LL;

#define FOR(x, b, e) for(int x=b; x<=(e); ++x)
#define FORD(x, b, e) for(int x=b; x>=(e); --x)
#define REP(x, n) for(int x=0; x<(n); ++x)
#define VAR(v, n) __typeof(n) v = (n)
#define ALL(c) (c).begin(), (c).end()
#define SIZE(x) ((int)(x).size())
#define FOREACH(i, c) for(VAR(i, (c).begin()); i != (c).end(); ++i)
#define PB push_back
#define ST first
#define ND second

int main() {
	ios_base::sync_with_stdio(0);
    int n;
    LL base = 1000000007;
    cin >> n;
    VI data(n);
    REP(i, n) cin >> data[i];
    sort(data.begin(), data.end());
    map<int, int> count;
    count[0] = 1;
    REP(i, n) {
        auto it = count.rbegin();
        while(it != count.rend() && it->ST >= data[i] - 1) {
            auto jt = it;
            ++it;
            count[data[i] + jt->ST] += jt->second;
            count[data[i] + jt->ST] %= base;
        }
    }
    int res = -1;
    for(auto it:count) {
        res += it.ND;
        res %= base;
    }
    cout << res << '\n';
    return 0;
}