#include <iostream>

 #include <cstdio>

 #include <cstring>

 #include <vector>

 #include <cmath>

 #include <algorithm>

 using namespace std;

 int dp[][];

 char str[];

 int judge(int x,int y)

 {

     if(str[x] == '['&&str[y] == ']')

     return ;

     else if(str[x] == '('&&str[y] == ')')

     return ;

     return ;

 }

 int dfs(int L,int R)

 {

     int maxz,i;

     maxz = ;

     if(dp[L][R] != -)

     return dp[L][R];

     if(L >= R)

     return ;

     if(judge(L,R))

     maxz = max(maxz, + dfs(L+,R-));

     for(i = L;i < R;i ++)

     maxz = max(maxz,dfs(L,i)+dfs(i+,R));

     return dp[L][R] = maxz;

 }

 int main()

 {

     int len;

     while(scanf("%s",str)!=EOF)

     {

         if(strcmp(str,"end") == )

         break;

         memset(dp,-,sizeof(dp));

         len = strlen(str);

         printf("%d\n",dfs(,len-));

     }

     return ;

 }