#include <algorithm>
#include <bitset>
#include <complex>
#include <deque>
#include <exception>
#include <fstream>
#include <functional>
#include <iomanip>
#include <ios>
#include <iosfwd>
#include <iostream>
#include <istream>
#include <iterator>
#include <limits>
#include <list>
#include <locale>
#include <map>
#include <memory>
#include <new>
#include <numeric>
#include <ostream>
#include <queue>
#include <set>
#include <sstream>
#include <stack>
#include <stdexcept>
#include <streambuf>
#include <string>
#include <typeinfo>
#include <utility>
#include <valarray>
#include <vector>
#include <climits>
#include <cstring>
#include <cassert>


using namespace std;
#define SZ(x) (int)(x.size())
#define REP(i, n) for(int i=0;i<n;++i)
#define FOR(i, a, b) for(int i=a;i<b;++i)
#define RREP(i, n) for(int i=n-1;i>=0;--i)
#define RFOR(i, a, b) for(int i=b-1;i>=a;--i)

#define all(x) begin(x),end(x)
#define dump(x) cerr<<#x<<" = "<<(x)<<endl
#define debug(x) cerr<<#x<<" = "<<(x)<<" (L"<<__LINE__<<")"<< endl;

using ll = long long;
using vi = vector<int>;
using vvi = vector<vi>;
using vll = vector<ll>;
using vvll = vector<vll>;
using P = pair<int, int>;
const double eps = 1e-8;
const ll MOD = 1000000007;
const int INF = INT_MAX / 2;
const ll LINF = LLONG_MAX / 2;

template<class T>
bool chmax(T &a, const T &b) {
    if (a < b) {
        a = b;
        return true;
    }
    return false;
}

template<class T>
bool chmin(T &a, const T &b) {
    if (b < a) {
        a = b;
        return true;
    }
    return false;
}


template<typename T1, typename T2>
ostream &operator<<(ostream &os, const pair<T1, T2> p) {
    os << p.first << ":" << p.second;
    return os;
}

template<class T>
ostream &operator<<(ostream &os, const vector<T> &v) {
    os << "[";
    REP(i, SZ(v)) {
        if (i) os << ", ";
        os << v[i];
    }
    return os << "]";
}

// edit
int N;
vector<ll> A;

vector<vector<ll>> dp;
vector<vector<bool>> vis;

ll dfs(int n, int c) {
    if (vis[n][c]) return dp[n][c];
    if (n == 0) {
        if (c <= 1) {
            return 0;
        } else {
            return -LINF;
        }
    }
    if (n == 1) {
        if (c == 0) {
            return A[0];
        } else if (c <= 2) {
            return 0;
        } else {
            return -LINF;
        }
    }

    vis[n][c] = true;

    ll &ret = dp[n][c];
    ret = dfs(n - 2, c) + A[n - 1];
    if (c >= 1) {
        chmax(ret, dfs(n - 1, c - 1));
    }

    return ret;
}

void solve() {
    cin >> N;
    A.resize(N);
    REP(i, N) cin >> A[i];

    dp.resize(N + 1, vector<ll>(3));
    vis.resize(N + 1, vector<bool>(3));

    ll ans = dfs(N, 1 + (N + 0) % 2);
    cout << ans << endl;


}


int main() {
    cin.tie(0);
    ios::sync_with_stdio(false);
    cout << fixed << setprecision(10);
//    std::ifstream in("input.txt");
//    std::cin.rdbuf(in.rdbuf());

    solve();


    return 0;
}

#include <bits/stdc++.h>

using namespace std;

int main(int argc, const char *argv[]) {
  string s;
  cin >> s;

  array<vector<int>, 26> p;
  for (int i = 0; i < s.size(); ++i) {
    p[s[i] - 'a'].push_back(i);
  }

  int l = -1, r = -1;
  for (int i = 0; i < p.size() && l < 0; ++i) {
    for (int j = 1; j < p[i].size() && l < 0; ++j) {
      if (p[i][j] - p[i][j - 1] <= 2) {
        l = p[i][j - 1] + 1;
        r = p[i][j] + 1;
      }
    }
  }

  cout << l << ' ' << r << '\n';
  return 0;
}