#include <bits/stdc++.h>

using namespace std;

// ifstream in("test.in");
// ofstream out("test.out");

struct Consumer {
    int consumed;
    string name;

    bool operator<(const Consumer& other) {
        // First compare x, then y
        return consumed < other.consumed;
    }
};




int main(int argc, char *argv[]) {
    string inName = "test.in";
    string outName = "test.out";
    
    if (argc > 1) {
        inName = argv[1];
        cout << "Using \"" << inName << "\" for test name" << endl;
    } else {
        cout << "Warning: no in name provided, defaulting to test.in" << endl;
    }

    if (argc > 2) {
        outName = argv[2];
        cout << "Using \"" << outName << "\" for out name" << endl;
    } else {
        cout << "Warning: no out name proviced, defaulting to test.out" << endl;
    }

    ifstream in(inName);
    ofstream out(outName);

    int n;
    in >> n;

    string tmpLName;
    string tmpFName;
    int tmpConsumption = 0;
    int totalConsumption = 0;
    // Consumer* consumers[n];
    vector<Consumer> consumers;
    consumers.reserve(n);

    for (int i = 0; i < n; i++) {
        in >> tmpLName;
        in >> tmpFName;
        in >> tmpConsumption;

        totalConsumption += tmpConsumption;
        Consumer* cons = new Consumer();
        consumers.push_back(*cons);
        (consumers[i].consumed) = tmpConsumption;
        (consumers[i].name) = tmpLName + " " + tmpFName;
    }
    
    sort(consumers.begin(), consumers.end());
    
    out << fixed << setprecision(2) << setw(10) << ((float)(totalConsumption) / (float)n) << endl;
    for (auto it = consumers.begin(); it != consumers.end(); it++) {
        #define consumer (*it)
        out << consumer.name << " " << consumer.consumed << endl;
    }
    // out << biggestConsumer << " " << maxConsumption << endl;
    // out << smallestConsumer << " " << minConsumption << endl;

    return 0;
}