money

#include<iostream>
#include<string>
#include<list>
#include<algorithm>
#include <iomanip>
#include <map>
using namespace std;
int main(){
    int a;
    cin>>a;
    map<string,int>m;
    int b;
    string w;
    int x;
    double t=0;
    int k=0;
    for(int i=0;i<a;i++){
        cin>>b;
        if(b == 1){
        cin>>w>>x;
        if(m[w] == 0){
            k++;
        }
            m[w] = m[w] + x;
            t = t + x;
        }
        else if(b == 2){
            cin>>w;
            t = t - m[w];
            m[w] = 0;
            k--;
        }
        else{
            cin>>w;
            cout<<m[w]<<endl;
        }
    }
    if(k != 0){
        t = t / k;
    }
    cout<<setprecision(2)<<fixed<<t;
    return 0;
}