1 #include <iostream>
2 #include <algorithm>
3 #include <cstring>
4 #include <cstdio>
5 #include <string>
6 #include <map>
7 #include <cmath>
8 #include <vector>
9
10 #define Faster ios::sync_with_stdio(false),cin.tie(0)
11 #define Read freopen("in.txt","r",stdin),freopen("out.txt","w",stdout)
12 #define Close fclose(stdin),fclose(stdout)
13 const int maxn = 150;
14 using namespace std;
15 const int MOD = 1e9+7;
16 typedef long long ll;
17
18 ll dp[maxn][maxn];
19 string s;
20
21 void solve(){
22 int len = s.size();
23 memset(dp, 0, sizeof(dp));
24
25 for(int i = 1;i < len;i++){
26 for(int j = 0;j + i < len;j++){
27 int k = i+j;
28 if((s[j] == '(' && s[k] == ')') || (s[j] == '[' && s[k] == ']'))
29 dp[j][k] = dp[j+1][k-1] + 2;
30 for(int l = j;l < k;l++){
31 dp[j][k] = max(dp[j][l] + dp[l+1][k],dp[j][k]);
32 }
33 }
34 }
35 cout << dp[0][len-1] << endl;
36 }
37
38 int main(){
39 Faster;
40 // string s;
41 while(cin >> s){
42 if(s == "end"){
43 break;
44 }
45 solve();
46 }
47 return 0;
48 }