#include <iostream>
#include <string>
using namespace std;
class User {
protected:
    string userType;
    string userID;
public:
    void getUserInfo() {
        cin >> userType >> userID;}};
class Workout : protected User {
protected:
    string goal;
    int logs;
    double totalCalories = 0;
    double totalDuration = 0;
public:
    void getWorkoutData() {
        cin >> goal >> logs;

        for (int i = 0; i < logs; i++) {
            double duration, calories;
            cin >> duration >> calories;

            if (duration <= 0 || calories <= 0) {
                cout << "Invalid input";
                exit(0); }
            totalDuration += duration;
            totalCalories += calories;  }}
    void calculateAverage() {
        double avg = totalCalories / totalDuration;
        cout << avg; }};
int main() {
    Workout w;
    w.getUserInfo();
    w.getWorkoutData();
    w.calculateAverage();
    return 0;
}