#include <bits/stdc++.h>
#include <atcoder/all>

using namespace std;
using namespace atcoder;
typedef long long ll;
#define rep(i, n) for (ll i = 0; i < (ll)(n); i++)
static const double pi = 3.141592653589793;
const ll INF = 1LL << 60;
const ll mod = 1000000007;
const ll imod = 998244353;
using mint = modint998244353;
vector<int> dx = {1, 0, -1, 0}, dy = {0, 1, 0, -1};
ll P(ll x, ll n) {
  ll ret = 1;
    while (n > 0) {
      if (n & 1) ret *= x;
      x *= x;
      n >>= 1;
  }
  return ret;
}

void seek(bool f){
  cout << (f ? "Yes" : "No") << endl;
}

int main(){
	int N;
	cin >> N;
	string s;
	cin >> s;
	int dp[N + 1][3];
	rep(i, N + 1){
		rep(j, 3){
			dp[i][j] = -1e9;
		}
	}
	dp[0][0] = 0;
	for(int i = 0; i < N; i++){
		for(int j = 0; j < 3; j++){
			dp[i + 1][j] = max(dp[i + 1][j], dp[i][j]);
		}
		if(s[i] == '+'){
			dp[i + 1][2] = max({dp[i + 1][2], max({dp[i][0], dp[i][1], dp[i][2]}) + 1});
		}
		if(s[i] == '0'){
			dp[i + 1][1] = max(dp[i + 1][1], dp[i][0] + 1);
		}
		if(s[i] == '-'){
			dp[i + 1][0] = max(dp[i + 1][0], dp[i][0] + 1);
		}
	}
	cout << max({dp[N][0], dp[N][1], dp[N][2]}) << endl;
}