// Copyright 2021 Jeisson Hidalgo <jeisson.hidalgo@ucr.ac.cr> CC-BY 4.0
#include <omp.h>
#include <iostream>
#include <vector>
int main(int argc, char* argv[]) {
int thread_count = omp_get_max_threads();
if (argc >= 2) {
thread_count = atoi(argv[1]);
}
std::vector<double> values;
double value = 0.0;
while (std::cin >> value) {
values.push_back(value);
}
double sum = 0.0;
for (size_t index = 0; index < values.size(); ++index) {
sum += values[index];
}
const double average = values.size() ? sum / values.size() : 0.0;
std::cout << average << std::endl;
}