/**
 * Solution as described in the solution outlines
 */

#include <iostream>
#include <vector>

typedef unsigned long long ull;

typedef struct Element {
	Element( ull spice, std::size_t id, std::size_t n ) {
		left = (id + n - 1) % n;
		right = (id + 1) % n;
		spiciness = spice;
		gain = spice;
	}
	std::size_t left = 0;
	std::size_t right = 0;
	ull spiciness;
	ull gain;
} Element;

bool try_solve( const std::vector<ull> &slices, ull tolerance ) {
	// create cyclic linked list
	const std::size_t n = slices.size();
	std::vector<Element> cll;
	cll.reserve( n );
	for( std::size_t i = 0; i < n; ++i ) {
		cll.emplace_back( slices[i], i, n );
	}

	std::size_t visit = 0;
	std::size_t visit_next = 0;
	do {
		visit = visit_next;
		Element &current = cll[visit];
		// Only one element left?
		if( visit == current.left )
			return true;

		Element &left = cll[current.left];
		Element &right = cll[current.right];
		if( tolerance >= current.spiciness ) {
			ull new_tolerance = tolerance + current.gain;
			if( left.spiciness <= new_tolerance ) {
				current.spiciness = std::min( current.spiciness, left.spiciness );
				current.gain += left.gain;
				current.left = left.left;
				cll[left.left].right = visit;
			} else if( right.spiciness <= new_tolerance) {
				current.spiciness = std::min( current.spiciness, right.spiciness );
				current.gain += right.gain;
				current.right = right.right;
				cll[right.right].left = visit;
			} else {
				visit_next = current.right;
			}
		} else {
			visit_next = current.right;
		}
	}	while( visit <= visit_next);

	return false;
}

int main() {
	ull n;
	std::cin >> n;
	std::vector<ull> slices(n);
	ull poss_tol = 0;
	for( ull &slice : slices ) {
		std::cin >> slice;
		poss_tol = std::max( poss_tol, slice );
	}
	// unsigned long long ftw
	if( poss_tol == 0 ) {
		std::cout << 0 << std::endl;
		return 0;
	}

	ull imposs_tol = 0;
	while( imposs_tol + 1 < poss_tol ) {
		ull test_tol = (imposs_tol + poss_tol) / 2;
		if( try_solve(slices, test_tol) )
			poss_tol = test_tol;
		else
			imposs_tol = test_tol;
	}

	std::cout << poss_tol << std::endl;

	return 0;
}