#include <iostream>
using namespace std;
int main()
{
int tab[10] = {};
int ile = 0;
char sign;
while( cin >> sign ){
if (sign == '-'){
if(ile == 0 || ile > 10){
cout << ":(" << endl;
}
else{
ile--;
cout << tab[ile];
}
}
else {
cin >> tab[ile];
if( ile > 9){
cout << ":("<<endl;
}
else {
cout << ":)" << endl;
if( ile < 10 ) ile++;
}
}
}
return 0;
}
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