#include <bits/stdc++.h>
#include <iostream>
#pragma region Header
#pragma GCC target("avx2")
#pragma GCC optimize("unroll-loops")
#pragma region TypeAlias
using i32 = int;
using u32 = unsigned int;
using i64 = long long;
using u64 = unsigned long long;
using i128 = __int128_t;
using u128 = __uint128_t;
using f64 = double;
using f80 = long double;
using f128 = __float128;
constexpr i32 operator"" _i32(u64 v)
{
    return v;
}
constexpr u32 operator"" _u32(u64 v)
{
    return v;
}
constexpr i64 operator"" _i64(u64 v)
{
    return v;
}
constexpr u64 operator"" _u64(u64 v)
{
    return v;
}
constexpr f64 operator"" _f64(f80 v)
{
    return v;
}
constexpr f80 operator"" _f80(f80 v)
{
    return v;
}
using Istream = std::istream;
using Ostream = std::ostream;
using Str = std::string;
template<typename T>
using Lt = std::less<T>;
template<typename T>
using Gt = std::greater<T>;
template<typename T>
using IList = std::initializer_list<T>;
template<int n>
using BSet = std::bitset<n>;
template<typename T1, typename T2>
using Pair = std::pair<T1, T2>;
template<typename... Ts>
using Tup = std::tuple<Ts...>;
template<typename T, int N>
using Arr = std::array<T, N>;
template<typename... Ts>
using Deq = std::deque<Ts...>;
template<typename... Ts>
using Set = std::set<Ts...>;
template<typename... Ts>
using MSet = std::multiset<Ts...>;
template<typename... Ts>
using USet = std::unordered_set<Ts...>;
template<typename... Ts>
using UMSet = std::unordered_multiset<Ts...>;
template<typename... Ts>
using Map = std::map<Ts...>;
template<typename... Ts>
using MMap = std::multimap<Ts...>;
template<typename... Ts>
using UMap = std::unordered_map<Ts...>;
template<typename... Ts>
using UMMap = std::unordered_multimap<Ts...>;
template<typename... Ts>
using Vec = std::vector<Ts...>;
template<typename... Ts>
using Stack = std::stack<Ts...>;
template<typename... Ts>
using Que = std::queue<Ts...>;
template<typename T>
using MaxHeap = std::priority_queue<T>;
template<typename T>
using MinHeap = std::priority_queue<T, Vec<T>, Gt<T>>;
#pragma endregion
#pragma region Constants
template<typename T>
constexpr T INF = std::numeric_limits<T>::max() / 4;
template<typename T>
constexpr T PI = T{3.141592653589793238462643383279502884};
template<typename T = u64>
constexpr T TEN(const int n)
{
    return n == 0 ? T{1} : TEN<T>(n - 1) * T{10};
}
#pragma endregion
#pragma region FuncAlias
template<typename T>
bool chmin(T& a, const T& b)
{
    if (a > b) {
        a = b;
        return true;
    } else {
        return false;
    }
}
template<typename T>
bool chmax(T& a, const T& b)
{
    if (a < b) {
        a = b;
        return true;
    } else {
        return false;
    }
}
template<typename T>
T fdiv(T x, T y)
{
    if (y < T{}) { x = -x, y = -y; }
    return x >= T{} ? x / y : (x - y + 1) / y;
}
template<typename T>
T cdiv(T x, T y)
{
    if (y < T{}) { x = -x, y = -y; }
    return x >= T{} ? (x + y - 1) / y : x / y;
}
template<typename T, typename I>
T power(T v, I n)
{
    T ans = 1;
    for (; n > 0; n >>= 1, v *= v) {
        if (n % 2 == 1) { ans *= v; }
    }
    return ans;
}
template<typename T, typename I>
T power(T v, I n, const T& e)
{
    T ans = e;
    for (; n > 0; n >>= 1, v *= v) {
        if (n % 2 == 1) { ans *= v; }
    }
    return ans;
}
template<typename T>
void fillAll(Vec<T>& vs, const T& v)
{
    std::fill(vs.begin(), vs.end(), v);
}
template<typename T, typename C = Lt<T>>
void sortAll(Vec<T>& vs, C comp = C{})
{
    std::sort(vs.begin(), vs.end(), comp);
}
template<typename T>
void reverseAll(Vec<T>& vs)
{
    std::reverse(vs.begin(), vs.end());
}
template<typename T>
void uniqueAll(Vec<T>& vs)
{
    sortAll(vs);
    vs.erase(std::unique(vs.begin(), vs.end()), vs.end());
}
template<typename T>
void iotaAll(Vec<T>& vs, T offset = T{})
{
    std::iota(vs.begin(), vs.end(), offset);
}
template<typename T, typename V = T>
V sumAll(const Vec<T>& vs)
{
    return std::accumulate(vs.begin(), vs.end(), V{});
}
template<typename T>
int minInd(const Vec<T>& vs)
{
    return std::min_element(vs.begin(), vs.end()) - vs.begin();
}
template<typename T>
int maxInd(const Vec<T>& vs)
{
    return std::max_element(vs.begin(), vs.end()) - vs.begin();
}
template<typename T>
int lbInd(const Vec<T>& vs, const T& v)
{
    return std::lower_bound(vs.begin(), vs.end(), v) - vs.begin();
}
template<typename T>
int ubInd(const Vec<T>& vs, const T& v)
{
    return std::lower_bound(vs.begin(), vs.end(), v) - vs.begin();
}
template<typename T, typename F>
Vec<T> genVec(int n, F gen)
{
    Vec<T> ans;
    std::generate_n(std::back_insert_iterator(ans), n, gen);
    return ans;
}
template<typename T>
Vec<T> iotaVec(int n, T offset = T{})
{
    Vec<T> ans(n);
    iotaAll(ans, offset);
    return ans;
}
template<typename T, typename F = Lt<T>>
Vec<T> iotaVec(const Vec<T>& vs, F comp = F{})
{
    auto is = iotaVec(vs.size(), 0);
    sortAll(is, [&](int i, int j) { return comp(vs[i], vs[j]); });
    return is;
}
template<typename T>
Vec<T> operator+=(Vec<T>& vs1, const Vec<T>& vs2)
{
    vs1.insert(vs1.end(), vs2.begin(), vs2.end());
    return vs1;
}
template<typename T>
Vec<T> operator+(const Vec<T>& vs1, const Vec<T>& vs2)
{
    return Vec<T>{vs1} += vs2;
}
#pragma endregion
#pragma region Show
#pragma endregion
#pragma region BitOps
constexpr int popcount(const u64 v)
{
    return v ? __builtin_popcountll(v) : 0;
}
constexpr int log2p1(const u64 v)
{
    return v ? 64 - __builtin_clzll(v) : 0;
}
constexpr int lsbp1(const u64 v)
{
    return __builtin_ffsll(v);
}
constexpr int clog(const u64 v)
{
    return v ? log2p1(v - 1) : 0;
}
constexpr u64 ceil2(const u64 v)
{
    return 1_u64 << clog(v);
}
constexpr u64 floor2(const u64 v)
{
    return v ? (1_u64 << (log2p1(v) - 1)) : 0_u64;
}
constexpr bool ispow2(const u64 v)
{
    return (v & (v - 1)) == 0;
}
constexpr bool btest(const u64 mask, const int ind)
{
    return (mask >> ind) & 1_u64;
}
#pragma endregion
#pragma region FixPoint
template<typename F>
struct Fixpoint : F
{
    Fixpoint(F&& f) : F{std::forward<F>(f)} {}
    template<typename... Args>
    auto operator()(Args&&... args) const
    {
        return F::operator()(*this, std::forward<Args>(args)...);
    }
};
#pragma endregion
#pragma region NdVec
template<typename T, int n, int i = 0>
auto ndVec(int const (&szs)[n], const T x = T{})
{
    if constexpr (i == n) {
        return x;
    } else {
        return std::vector(szs[i], ndVec<T, n, i + 1>(szs, x));
    }
}
#pragma endregion
#pragma region Range
class range
{
private:
    struct itr
    {
        itr(int start = 0, int step = 1) : m_cnt{start}, m_step{step} {}
        bool operator!=(const itr& it) const
        {
            return m_cnt != it.m_cnt;
        }
        int operator*()
        {
            return m_cnt;
        }
        itr& operator++()
        {
            m_cnt += m_step;
            return *this;
        }
        int m_cnt, m_step;
    };
    int m_start, m_end, m_step;
public:
    range(int start, int end, int step = 1)
        : m_start{start}, m_end{end}, m_step{step}
    {
        assert(m_step == 1 or m_step == -1);
    }
    itr begin() const
    {
        return itr{m_start, m_step};
    }
    itr end() const
    {
        return itr{m_end, m_step};
    }
};
range rep(int end)
{
    return range(0, end, 1);
}
range per(int rend)
{
    return range(rend - 1, -1, -1);
}
class ndRep
{
private:
    struct itr
    {
        itr(const Vec<int>& ns) : m_ns{ns}, m_cs(ns.size(), 0), m_end{false} {}
        bool operator!=(const itr&) const
        {
            return not m_end;
        }
        const Vec<int>& operator*()
        {
            return m_cs;
        }
        itr& operator++()
        {
            for (const int i : per(m_ns.size())) {
                m_cs[i]++;
                if (m_cs[i] < m_ns[i]) {
                    break;
                } else {
                    if (i == 0) { m_end = true; }
                    m_cs[i] = 0;
                }
            }
            return *this;
        }
        Vec<int> m_ns, m_cs;
        bool m_end;
    };
    Vec<int> m_ns;
public:
    ndRep(const Vec<int>& ns) : m_ns{ns} {}
    itr begin() const
    {
        return itr{m_ns};
    }
    itr end() const
    {
        return itr{m_ns};
    }
};
#pragma endregion
#pragma message("[REFS] Xoshiro: https://prng.di.unimi.it")
#pragma region Xoshiro
namespace xoshiro_impl {
u64 x;
u64 next()
{
    uint64_t z = (x += 0x9e3779b97f4a7c15);
    z = (z ^ (z >> 30)) * 0xbf58476d1ce4e5b9;
    z = (z ^ (z >> 27)) * 0x94d049bb133111eb;
    return z ^ (z >> 31);
}
}
class Xoshiro32
{
public:
    using result_type = u32;
    using T = result_type;
    Xoshiro32(T seed = 0)
    {
        xoshiro_impl::x = seed;
        s[0] = xoshiro_impl::next();
        s[1] = xoshiro_impl::next();
        s[2] = xoshiro_impl::next();
        s[3] = xoshiro_impl::next();
    }
    static constexpr T min()
    {
        return std::numeric_limits<T>::min();
    }
    static constexpr T max()
    {
        return std::numeric_limits<T>::max();
    }
    T operator()()
    {
        return next();
    }
private:
    static constexpr T rotl(const T x, int k)
    {
        return (x << k) | (x >> (32 - k));
    }
    T next()
    {
        const T ans = rotl(s[1] * 5, 7) * 9;
        const T t = s[1] << 9;
        s[2] ^= s[0];
        s[3] ^= s[1];
        s[1] ^= s[2];
        s[0] ^= s[3];
        s[2] ^= t;
        s[3] = rotl(s[3], 11);
        return ans;
    }
    T s[4];
};
class Xoshiro64
{
public:
    using result_type = u64;
    using T = result_type;
    Xoshiro64(T seed = 0)
    {
        xoshiro_impl::x = seed;
        s[0] = xoshiro_impl::next();
        s[1] = xoshiro_impl::next();
        s[2] = xoshiro_impl::next();
        s[3] = xoshiro_impl::next();
    }
    static constexpr T min()
    {
        return std::numeric_limits<T>::min();
    }
    static constexpr T max()
    {
        return std::numeric_limits<T>::max();
    }
    T operator()()
    {
        return next();
    }
private:
    static constexpr T rotl(const T x, int k)
    {
        return (x << k) | (x >> (64 - k));
    }
    T next()
    {
        const T ans = rotl(s[1] * 5, 7) * 9;
        const T t = s[1] << 17;
        s[2] ^= s[0];
        s[3] ^= s[1];
        s[1] ^= s[2];
        s[0] ^= s[3];
        s[2] ^= t;
        s[3] = rotl(s[3], 45);
        return ans;
    }
    T s[4];
};
#pragma endregion
#pragma region RNG
template<typename Rng>
class RNG
{
public:
    using result_type = typename Rng::result_type;
    using T = result_type;
    static constexpr T min()
    {
        return Rng::min();
    }
    static constexpr T max()
    {
        return Rng::max();
    }
    RNG() : RNG(std::random_device{}()) {}
    RNG(T seed) : m_rng(seed) {}
    T operator()()
    {
        return m_rng();
    }
    template<typename T>
    T val(T min, T max)
    {
        return std::uniform_int_distribution<T>(min, max)(m_rng);
    }
    template<typename T>
    Pair<T, T> pair(T min, T max)
    {
        return std::minmax({val<T>(min, max), val<T>(min, max)});
    }
    template<typename T>
    Vec<T> vec(int n, T min, T max)
    {
        return genVec<T>(n, [&]() { return val<T>(min, max); });
    }
    template<typename T>
    Vec<Vec<T>> vvec(int n, int m, T min, T max)
    {
        return genVec<Vec<T>>(n, [&]() { return vec(m, min, max); });
    }
private:
    Rng m_rng;
};
RNG<std::mt19937> rng;
RNG<std::mt19937_64> rng64;
RNG<Xoshiro32> rng_xo;
RNG<Xoshiro64> rng_xo64;
#pragma endregion
struct modinfo
{
    void set_mod(const u32 nmod) { mod = nmod; }
    u32 mod, root, max2p;
};
template<const modinfo& info>
class modint
{
public:
    static constexpr const u32& mod = info.mod;
    static constexpr const u32& root = info.root;
    static constexpr const u32& max2p = info.max2p;
    constexpr modint() : m_val{0} {}
    constexpr modint(const i64 v) : m_val{normll(v)} {}
    constexpr void set_raw(const u32 v) { m_val = v; }
    constexpr modint operator-() const { return modint{0} - (*this); }
    constexpr modint& operator+=(const modint& m) { return m_val = norm(m_val + m()), *this; }
    constexpr modint& operator-=(const modint& m) { return m_val = norm(m_val + mod - m()), *this; }
    constexpr modint& operator*=(const modint& m) { return m_val = normll((i64)m_val * (i64)m() % (i64)mod), *this; }
    constexpr modint& operator/=(const modint& m) { return *this *= m.inv(); }
    constexpr modint operator+(const modint& m) const { return modint{*this} += m; }
    constexpr modint operator-(const modint& m) const { return modint{*this} -= m; }
    constexpr modint operator*(const modint& m) const { return modint{*this} *= m; }
    constexpr modint operator/(const modint& m) const { return modint{*this} /= m; }
    constexpr bool operator==(const modint& m) const { return m_val == m(); }
    constexpr bool operator!=(const modint& m) const { return not(*this == m); }
    friend std::istream& operator>>(std::istream& is, modint& m)
    {
        i64 v;
        return is >> v, m = v, is;
    }
    friend std::ostream& operator<<(std::ostream& os, const modint& m) { return os << m(); }
    constexpr u32 get() const { return m_val; }
    constexpr u32 operator()() const { return m_val; }
    template<typename Int>
    constexpr modint pow(Int n) const { return power(*this, n); }
    constexpr modint inv() const { return pow(mod - 2); }
    static modint sinv(const u32 n)
    {
        static std::vector<modint> is{1, 1};
        for (u32 i = (u32)is.size(); i <= n; i++) { is.push_back(-is[mod % i] * (mod / i)); }
        return is[n];
    }
    static modint fact(const u32 n)
    {
        static std::vector<modint> fs{1, 1};
        for (u32 i = (u32)fs.size(); i <= n; i++) { fs.push_back(fs.back() * i); }
        return fs[n];
    }
    static modint ifact(const u32 n)
    {
        static std::vector<modint> ifs{1, 1};
        for (u32 i = (u32)ifs.size(); i <= n; i++) { ifs.push_back(ifs.back() * sinv(i)); }
        return ifs[n];
    }
    static modint comb(const int n, const int k) { return k > n or k < 0 ? modint{0} : fact(n) * ifact(n - k) * ifact(k); }
private:
    static constexpr u32 norm(const u32 x) { return x < mod ? x : x - mod; }
    static constexpr u32 normll(const i64 x) { return norm(u32(x % (i64)mod + (i64)mod)); }
    u32 m_val;
};
constexpr modinfo modinfo_1000000007 = {1000000007, 5, 1};
constexpr modinfo modinfo_998244353 = {998244353, 3, 23};
using modint_1000000007 = modint<modinfo_1000000007>;
using modint_998244353 = modint<modinfo_998244353>;
#pragma region Printer
class printer
{
public:
    printer(Ostream& os = std::cout) : m_os{os}
    {
        m_os << std::fixed << std::setprecision(15);
    }
    template<typename... Args>
    int operator()(const Args&... args)
    {
        dump(args...);
        return 0;
    }
    template<typename... Args>
    int ln(const Args&... args)
    {
        dump(args...), m_os << '\n';
        return 0;
    }
    template<typename... Args>
    int el(const Args&... args)
    {
        dump(args...), m_os << std::endl;
        return 0;
    }
private:
    template<typename T>
    void dump(const T& v)
    {
        m_os << v;
    }
    template<typename T>
    void dump(const Vec<T>& vs)
    {
        for (const int i : rep(vs.size())) {
            m_os << (i ? " " : ""), dump(vs[i]);
        }
    }
    template<typename T>
    void dump(const Vec<Vec<T>>& vss)
    {
        for (const int i : rep(vss.size())) {
            m_os << (i ? "" : "\n"), dump(vss[i]);
        }
    }
    template<typename T, typename... Ts>
    int dump(const T& v, const Ts&... args)
    {
        dump(v), m_os << ' ', dump(args...);
        return 0;
    }
    Ostream& m_os;
};
printer out;
#pragma endregion
#pragma region Scanner
class scanner
{
public:
    scanner(Istream& is = std::cin) : m_is{is}
    {
        m_is.tie(nullptr)->sync_with_stdio(false);
    }
    template<typename T>
    T val()
    {
        T v;
        return m_is >> v, v;
    }
    template<typename T>
    T val(T offset)
    {
        return val<T>() - offset;
    }
    template<typename T>
    Vec<T> vec(int n)
    {
        return genVec<T>(n, [&]() { return val<T>(); });
    }
    template<typename T>
    Vec<T> vec(int n, T offset)
    {
        return genVec<T>(n, [&]() { return val<T>(offset); });
    }
    template<typename T>
    Vec<Vec<T>> vvec(int n, int m)
    {
        return genVec<Vec<T>>(n, [&]() { return vec<T>(m); });
    }
    template<typename T>
    Vec<Vec<T>> vvec(int n, int m, const T offset)
    {
        return genVec<Vec<T>>(n, [&]() { return vec<T>(m, offset); });
    }
    template<typename... Args>
    auto tup()
    {
        return Tup<Args...>{val<Args>()...};
    }
    template<typename... Args>
    auto tup(const Args&... offsets)
    {
        return Tup<Args...>{val<Args>(offsets)...};
    }
private:
    Istream& m_is;
};
scanner in;
#pragma endregion
#pragma endregion
int main()
{
    const auto N = in.val<int>();
    const auto as = in.vec<int>(N);
    Vec<int> os;
    int l = 0;
    for (const int i : rep(N)) {
        if (as[i] == 1) {
            l++;
        } else {
            if (l) { os.push_back(l); }
            l = 0;
        }
    }
    if (l) { os.push_back(l); }
    void(0);
    i64 ans = (i64)N * (N + 1) / 2;
    for (const i64 o : os) {
        ans -= o * (o + 1) / 2;
    };
    out.ln(ans);
    return 0;
}