#include <bits/stdc++.h>
using namespace std;
const int MAXN = 200005;
int L[MAXN], R[MAXN];
long long V[MAXN];
struct comp {
bool operator () (int x, int y) const {
return V[x] > V[y] ||
(V[x] == V[y] && x > y);
}
};
int main() {
cin.tie(0)->sync_with_stdio(0);
int N; cin >> N;
set<int, comp> S;
for (int i = 1; i <= N; i++) {
cin >> V[i];
L[i] = R[i] = i;
S.insert(i);
}
long long res = 0;
while (S.size()) {
auto it = S.begin();
S.erase(it);
int l = *it, r = R[*it];
res += V[l];
if (S.count(r + 1) &&
S.count(L[l - 1])) {
S.erase(r + 1);
V[l] -= V[r + 1];
r = R[r + 1];
S.erase(L[l - 1]);
V[L[l - 1]] -= V[l];
l = L[l - 1];
L[r] = l; R[l] = r;
S.insert(l);
} else {
S.erase(r + 1);
S.erase(L[l - 1]);
}
cout << res << '\n';
}
}
