#include <iostream>
#include <ranges>
#include <vector>
#define sv std::ranges::views::

using namespace std;
using tp = long long int;

signed main() {
  long double n, sum = 0;
  freopen("/dev/stdin", "r", stdin);
  while (~scanf("%Lf", &n)) {
    sum += n * 1e6;
  }
  printf("%.5Lf", sum / 1e6);
  return EXIT_SUCCESS;
}

/*
 */

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