//edited by Eddy
//from BeiHang Univ
//any questions,contact oeddyo@gmail.com
#include <iostream>
using namespace std;
#define MAX 101
int res[MAX][MAX];
int pos[MAX][MAX];
void output(char a[],int b,int e)

{
if(b>e)
return ;
if(pos[b][e]==-1)
{
cout<<a[b];
output(a,b+1,e-1);
cout<<a[e];
return ;
}
if(b==e)
{
if(a[b]=='('||a[e]==')')
cout<<"()";
else if(a[b]=='['||a[e]==']')
cout<<"[]";
return ;
}
output(a,b,pos[b][e]);
output(a,pos[b][e]+1,e);
}
int main()

{
char s[120];
while(cin.getline(s,101))
{
memset(res,0,sizeof(res));
memset(pos,0,sizeof(pos));
int s_size=strlen(s);
for(int i=0;s[i];i++)
{
res[i][i]=1;
for(int j=i-1; j>=0; j--)
{
if(s[j]=='('&&s[i]==')'||s[j]=='['&&s[i]==']')
{
res[j][i]=res[j+1][i-1];
pos[j][i]=-1; //標記-1即不用多補
}
else
{
res[j][i]=10000000;
}
for(int k=j;k<i;k++) //經典代碼。。。多理解
{
int t=res[j][k]+res[k+1][i];
if(t<res[j][i])
{
res[j][i]=t;
pos[j][i]=k;
}
}
}
}
output(s,0,s_size-1);
cout<<endl;
}
return 0;
}

