#include <iostream>
#include <algorithm>
#include <cmath>
#include <string>
#include <cstdlib>
#include <vector>
#include <queue>
#include <set>
#include <map>
#include <cstdio>
#include <iomanip>

#define SWS ios_base::sync_with_stdio(0); cin.tie(0); cout.tie(0)
#define pb push_back
#define ppb pop_back
#define ft first
#define sd second
#define read freopen("prices.in", "r", stdin)
#define write freopen("prices.out", "w", stdout)
#define files read; write

using namespace std;

typedef long long ll;
typedef long double ld;
typedef pair<int, int> pii;

const int Z = (int)3e3 + 228;
const int N = (int)3e5 + 228;
const int MOD = (int)1e9 + 7;
const int INF = (int) 1e9 + 228;

int dp[111][111];

int main()
{
	SWS;
	//files;
	string s;
	cin >> s;
	int n = s.length();
	for (int i = 0; i < n; i++)
		dp[i][i] = 1;
	for (int len = 2; len <= n; len++)
		for (int i = 0; i < n; i++)
		{
			int l = i, r = i + len - 1;
			if (r >= n) break;
			if (len == 2 && s[l] == '(' && s[r] == ')')
			{
				dp[l][r] = 0;
				continue;
			}
			dp[l][r] = INF;
			for (int k = l; k < r; k++)
				dp[l][r] = min(dp[l][r], dp[l][k] + dp[k + 1][r]);
			if (s[l] == '(' && s[r] == ')') dp[l][r] = min(dp[l][r], dp[l + 1][r - 1]);
		}
	cout << dp[0][n - 1];
	return 0;
}
//()x)y)