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#include <bits/stdc++.h>
using namespace std;

#define fastIO ios_base::sync_with_stdio(0); cin.tie(0)
#define dbg(...) "[" << #__VA_ARGS__ ": " << (__VA_ARGS__) << "] "

#define fi first
#define se second
#define all(x) begin(x), end(x)
#define rall(x) rbegin(x), rend(x)
#define mt make_tuple

#define readRepeatInt int _t; cin >> _t; while (_t--)
#define repeat(i, x) for (int i = 0; i < (x); ++i)
#define repeatRev(i, x) for (int i = (x) - 1; i >= 0; --i)

using ll =  long long;                  using vb = vector<bool>;
// using i128 = __int128;               using vi128 = vector<i128>;
using ull = unsigned long long;         using vull = vector<ull>;
using vll = vector<ll>;                 using vvll = vector<vll>;
using vi = vector<int>;                 using vvi = vector<vi>;

using pi = pair<int, int>;              using vpi = vector<pi>;
using pll = pair<ll, ll>;               using vpll = vector<pll>;

using si = set<int>;                    using sll = set<ll>;
using usi = unordered_set<int>;         using usll = unordered_set<ll>;
using di = deque<int>;                  using dll = deque<ll>;
using mi = map<int, int>;               using mll = map<ll, ll>;
using umi = unordered_map<int, int>;    using umll = unordered_map<ll, ll>;

using vsi = vector<si>;                 using vsll = vector<sll>;
using vusi = vector<usi>;               using vusll = vector<usll>;

template<typename A, typename B> inline A& maxi(A& a, B b) {return a = max(a, A(b)); }
template<typename A, typename B> inline A& mini(A& a, B b) {return a = min(a, A(b)); }

template <typename T> struct reversion_wrapper {T& iterable; };
template <typename T> reversion_wrapper<T> reverse(T&& iterable) {return {iterable}; }
template <typename T> auto begin(reversion_wrapper<T> w) {return rbegin(w.iterable); }
template <typename T> auto end(reversion_wrapper<T> w) {return rend(w.iterable); }

template<typename Iter> inline ostream& streamByIterators(ostream &os, Iter beg, Iter end) {os << '{'; if (beg != end) {os << *beg; while (++beg != end) os << ", " << *beg; }; return os << '}'; }
template<typename T> inline ostream& operator<<(ostream &os, const vector<T> &v) {return streamByIterators(os, v.begin(), v.end()); }
template<typename T> inline ostream& operator<<(ostream &os, const deque<T> &d) {return streamByIterators(os, d.begin(), d.end()); }
template<typename T> inline ostream& operator<<(ostream &os, const set<T> &s) {return streamByIterators(os, s.begin(), s.end()); }
template<typename T, typename V> inline ostream& operator<<(ostream &os, const map<T, V> &m) {return streamByIterators(os, m.begin(), m.end()); }
template<typename T> inline ostream& operator<<(ostream &os, const unordered_set<T> &s) {return streamByIterators(os, s.begin(), s.end()); }
template<typename T, typename V> inline ostream& operator<<(ostream &os, const unordered_map<T, V> &m) {return streamByIterators(os, m.begin(), m.end()); }
template<typename T, size_t size> inline ostream& operator<<(ostream &os, const array<T, size> &a) {return streamByIterators(os, a.begin(), a.end()); }
template<typename A, typename B> inline ostream& operator<<(ostream &os, const pair<A, B> &p) {return os << '(' << p.first << ", " << p.second << ')'; }
 
template<typename T> inline istream& operator>>(istream &is, vector<T> &v) {for (T& t : v) is >> t; return is; }
template<typename T> inline istream& operator>>(istream &is, deque<T> &d) {for (T& t : d) is >> t; return is;}
template<typename T, size_t size> inline istream& operator>>(istream &is, array<T, size> &a) {for (T& t : a) is >> t; return is; }
template<typename A, typename B> inline istream& operator>>(istream &is, pair<A, B> &p) {return is >> p.first >> p.second; }

template<typename T, typename V> T constexpr myPow(T base, V exp) {T ans(1); while (exp > 0) {if (exp & 1) ans *= base; base *= base; exp >>= 1; } return ans; }
template<typename T, typename V> T constexpr myPowMod(T base, T mod, V exp) {T ans(1); while (exp > 0) {if (exp & 1) ans = (ans * base) % mod; base = (base * base) % mod; exp >>= 1; } return ans; }
template<typename T> inline constexpr T myMod(T val, T mod) {val %= mod; if (val < 0) val += mod; return val; }
// mt19937_64 rng(chrono::high_resolution_clock::now().time_since_epoch().count());
// uniform_int_distribution<int> dist(1, MX);

template<typename T> pair<T, T> extEuclidean(T a, T b)
{
    pair<T, T> s = {1, 0};
    pair<T, T> r = {a, b};

    while (r.second)
    {
        T q = r.first / r.second;
        r = {r.second, r.first - q * r.second};
        s = {s.second, s.first - q * s.second};
    }

    return {s.first, b ? (r.first - s.first * a) / b : 0};
}

template<typename T, T modulo> struct modBase
{
    T val;

    modBase() : val(0) {}
    modBase(T v)
    {
        if (0 <= v && v < modulo)
            val = v;
        else
            val = myMod(v, modulo);
    }

    using baseType = T;

    static T modValue() {return modulo; }
    T value() const {return val; }

    // modBase inverse() const {/*assert(gcd(modulo, val) == 1);*/ return extEuclidean(modulo, val).second; }
    modBase inverse() const {return myPow(*this, modulo - 2); }

    modBase operator-() const {modBase ret; if (val) ret.val = modulo - val; return ret; }
    modBase operator+() const {return *this; }

    modBase& operator+=(modBase const& x) {val += x.val; if (val >= modulo) val -= modulo; return *this; }
    modBase& operator-=(modBase const& x) {val -= x.val; if (val < 0) val += modulo; return *this; }
    modBase& operator*=(modBase const& x) {val = myMod(val * x.val, modulo); return *this; }
    modBase& operator/=(modBase const& x) {return (*this) *= x.inverse(); }

    friend modBase operator+(const modBase& a, const modBase& b) {modBase ret(a); return ret += b; }
    friend modBase operator-(const modBase& a, const modBase& b) {modBase ret(a); return ret -= b; }
    friend modBase operator*(const modBase& a, const modBase& b) {modBase ret(a); return ret *= b; }
    friend modBase operator/(const modBase& a, const modBase& b) {modBase ret(a); return ret /= b; }

    modBase& operator++() {return (*this) += 1; }
    modBase operator++(int) {modBase tmp(*this); operator++(); return tmp; }
    modBase& operator--() {return (*this) -= 1; }
    modBase operator--(int) {modBase tmp(*this); operator--(); return tmp; }

    template<typename X> static modBase factorial(X v) {modBase ret(1); for (modBase i(1); --v >= 0 ; ++i) ret *= i; return ret; }

    friend ostream& operator<<(ostream &os, const modBase& m) {return os << m.val; }
    friend bool operator<(const modBase& a, const modBase& b) {return a.val < b.val; }
    friend bool operator==(const modBase& a, const modBase& b) {return a.val == b.val; }
    friend bool operator!=(const modBase& a, const modBase& b) {return a.val != b.val; }
};

template<ll M> using modInteger = modBase<ll, M>;
using mod1e9p7 = modInteger<ll(1e9 + 7)>;
using mod1e9p9 = modInteger<ll(1e9 + 9)>;
using mod998s = modInteger<998244353LL>;
using mods = pair<mod1e9p7, mod1e9p9>;

struct seg
{
    int n;
    vector<mod1e9p7> v;
    
    void reset(int m)
    {
        n = 1;
        while (n < m)
            n *= 2;
        v.resize(2 * n);
        fill(all(v), 0);
    }
    seg(int m = 1) {reset(m); }
    
    void add(int p, mod1e9p7 x)
    {
        p += n;
        v[p] += x;
        p /= 2;
        
        while (p)
        {
            v[p] = v[2*p] + v[2*p+1];
            p /= 2;
        }
    }
    
    mod1e9p7 seg_sum_int(int l, int r, int node, int nl, int nr)
    {
        if (l == nl && r == nr)
            return v[node];
            
        int mid = (nl+nr) / 2;
            
        if (r <= mid)
            return seg_sum_int(l,r,node*2,nl,mid);
        else if (l > mid)
            return seg_sum_int(l,r,node*2+1,mid+1,nr);
            
        return seg_sum_int(l,mid,node*2, nl,mid) + seg_sum_int(mid+1,r,node*2+1, mid+1,nr);
    }
    mod1e9p7 seg_sum(int l, int r)
    {
        if (l > r)
            return 0;
        return seg_sum_int(l,r,1,0,n-1);
    }
};

int32_t main()
{
    fastIO;
    
    int n;
    cin >> n;
    vll vals(n);
    cin >> vals;
    
    map<ll, int> toInd;
    toInd[0] = -1;
    mod1e9p7 pref;
    for (ll x : vals)
    {
        pref -= x;
        toInd[pref.val] = -1;
    }
    
    int ii = 0;
    for (auto& [_, t] : toInd)
        t = ii++;
    
    seg segs[2] = {n+5, n+5};
    int MX = segs[0].n - 1;
    
    segs[0].add(0, 1);
    
    pref = 0;
    repeat(i, n)
    {
        pref -= vals[i];
        
        int in = toInd[pref.val];
        
        mod1e9p7 toAdd = segs[pref.val&1].seg_sum(in, MX) + segs[(pref.val&1)^1].seg_sum(0, in-1);
        
        if (i == n-1)
            cout << toAdd.val;
        
        segs[pref.val&1].add(in, toAdd);
    }

    return 0;
}