#define _CRT_SECURE_NO_WARNINGS
//#define _GLIBCXX_DEBUG
#include <bits/stdc++.h>
using namespace std;
typedef long long ll;
typedef vector<int> vi;
typedef vector<vi> vvi;
typedef pair<int,int> pii;
#define all(c) (c).begin(), (c).end()
#define loop(i,a,b) for(ll i=a; i<ll(b); i++)
#define rep(i,b) loop(i,0,b)
#define pb push_back
#define eb emplace_back
#define mp make_pair
#define mt make_tuple
template<class T> ostream & operator<<(ostream & os, vector<T> const &);
template<int n, class...T> typename enable_if<(n>=sizeof...(T))>::type _ot(ostream &, tuple<T...> const &){}
template<int n, class...T> typename enable_if<(n< sizeof...(T))>::type _ot(ostream & os, tuple<T...> const & t){ os << (n==0?"":" ") << get<n>(t); _ot<n+1>(os, t); }
template<class...T> ostream & operator<<(ostream & os, tuple<T...> const & t){ _ot<0>(os, t); return os; }
template<class T, class U> ostream & operator<<(ostream & os, pair<T,U> const & p){ return os << "(" << p.first << ", " << p.second << ") "; }
template<class T> ostream & operator<<(ostream & os, vector<T> const & v){ rep(i,v.size()) os << v[i] << (i+1==(int)v.size()?"":" "); return os; }
#ifdef DEBUG
#define dump(...) (cerr<<#__VA_ARGS__<<" = "<<mt(__VA_ARGS__)<<" ["<<__LINE__<<"]"<<endl)
#else
#define dump(...)
#endif

// Verify : http://judge.u-aizu.ac.jp/onlinejudge/description.jsp?id=1102
// Verify : http://judge.u-aizu.ac.jp/onlinejudge/description.jsp?id=0264

typedef complex<int> comp;

class ExpressionParser {
public:
    typedef comp C;
    struct overflow {};
    struct parseError {
        string mes;
        parseError(string const & s) : mes(s) {}
    };
    explicit ExpressionParser(string const & s)
        : e(s), pos(e.begin()) {
    }
    C parse() {
        return expr(pos);
    }

private:
    typedef string::iterator iter;
    string e;
    iter pos;

    bool valid(C c){
        return abs(c.real()) <= 10000 && abs(c.imag()) <= 10000;
    }

    bool ispm(char c){
        return c=='+' || c=='-';
    }
    bool ispd(char c){
        return c=='*' || c=='/';
    }
    bool isdig(char c){
        return isdigit(c);
    }
    bool isi(char c){
        return c == 'i';
    }
    bool isdigi(char c){
        return isdigit(c) || isi(c);
    }
    bool isPar(char c){
        return c == '(';
    }

    bool isBegNum(iter p){
        return isdigi(*p);
    }
    bool isBegFact(iter p){
        return isBegNum(p) || isPar(*p);
    }
    bool isBegTerm(iter p){
        return isBegFact(p);
    }
    bool isBegExp(iter p){
        return isBegTerm(p);
    }

    bool isEndNum(iter p){
        return p==e.end() || *p==')' || ispm(*p) || ispd(*p);
    }
    bool isEndFact(iter p){
        return p==e.end() || *p==')' || ispm(*p) || ispd(*p);
    }
    bool isEndTerm(iter p){
        return p==e.end() || *p==')' || *p=='+' || *p=='-';
    }
    bool isEndExp(iter p){
        return p==e.end() || *p==')';
    }

    C num(iter & p){
        if(!isBegNum(p)) throw parseError("num begin");
        C res(0);
        if(isdig(*p)){
            while (isdig(*p)){
                res *= C(10);
                res += C(*p-'0');
                if(!valid(res)) throw overflow();
                p++;
            }
        }
        if(isi(*p)){
            res = C(0,1);
            p++;
        }
        if(!isEndNum(p)) throw parseError("num end");
        if(!valid(res)) throw overflow();
        dump(res);
        return res;
    }

    C fact(iter & p){
        if(!isBegFact(p)) throw parseError("fact begin");
        C res(0);
        if(*p=='('){
            p++;
            res += expr(p);
            p++;
        } else if (isdigit(*p) || *p == 'i'){
            res += num(p);
        }

        if(!isEndFact(p)) throw parseError("fact end");
        if(!valid(res)) throw overflow();
        return res;
    }

    C term(iter & p){
        if(!isBegTerm(p)) throw parseError("term begin");
        C res = fact(p);
        while(1){
            if(*p=='*'){
                p++;
                res *= fact(p);
            } else if (*p=='/'){
                p++;
                res /= fact(p);
            } else {
                break;
            }
            if(!valid(res)) throw overflow();
        }

        if(!isEndTerm(p)) throw parseError("term end");
        if(!valid(res)) throw overflow();
        return res;
    }

    C expr(iter & p){
        if(!isBegExp(p)) throw parseError("exp begin");
        C res = term(p);
        while(1){
            if(*p=='+'){
                p++;
                res += term(p);
            } else if (*p=='-'){
                p++;
                res -= term(p);
            } else {
                break;
            }
            if(!valid(res)) throw overflow();
        }
        if(!isEndExp(p)) throw parseError("exp end");
        if(!valid(res)) throw overflow();
        return res;
    }
};

void print(const comp &z) {
    if (z.imag() == 0){
        cout << z.real() << endl;
    } else if (z.real() == 0) {
        cout << z.imag() << "i" << endl;
    } else {
        cout << z.real();
        if (z.imag() > 0)
            cout << "+";
        cout << z.imag() << "i" << endl;
    }
}

int main() {
    string s;
    while (cin >> s) {
        try {
            ExpressionParser p(s);
            comp z = p.parse();
            print(z);
        } catch(const ExpressionParser::overflow) {
            cout << "overflow" << endl;
        } catch(...){
        }
    }
}

Measured memory_bytes: 1276