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

#define int long long

void testcase()
{
	int N;
	cin >> N;

	string S;
	cin >> S;

	vector<int> list_minus(N + 1, 0), list_zero(N + 1, 0), list_plus(N + 1, 0);
	for (int i = 0; i < N; i++)
	{
		list_minus[i + 1] = list_minus[i] + (S[i] == '-' ? 1 : 0);
		list_zero[i + 1] = list_zero[i] + (S[i] == '0' ? 1 : 0);
		list_plus[i + 1] = list_plus[i] + (S[i] == '+' ? 1 : 0);
	}
	int total_plus = list_plus[N];

	vector<int> next_zero(N + 1), next_plus(N + 1);
	next_zero[N] = next_plus[N] = N;
	for (int i = N - 1; i >= 0; --i)
	{
		if (S[i] == '0')
			next_zero[i] = i;
		else
			next_zero[i] = next_zero[i + 1];
		if (S[i] == '+')
			next_plus[i] = i;
		else
			next_plus[i] = next_plus[i + 1];
	}

	int max_count = 0;
	for (int i = 0; i < N; i++)
	{
		int count = (list_minus[min(next_zero[i], next_plus[i])] - list_minus[i]) + (list_zero[next_plus[i]] - list_zero[i]) + (list_plus[N] - list_plus[i]);

		max_count = max(max_count, count);
	}

	cout << max_count << '\n';
}

int32_t main()
{
	ios::sync_with_stdio(false);
	cin.tie(0);
	cout.tie(0);

	testcase();
	return 0;
}