#include <iostream> #include <iomanip> using namespace std; int main() { int tab[100]; int x = 0, n = 0, sum = 0; cin >> x; while(x >= 0) { tab[n] = x; n++; cin >> x; } int length = n; for(int i = 0; i < length; i++) { sum += tab[i]; } float moy = (float)sum / length; cout << setiosflags(ios::fixed | ios::showpoint) << setprecision(2) << moy << '\n'; return 0; } // main()