#include <bits/stdc++.h>
#define MULTI 10000000000

using namespace std;

int N;

int main(void){
    
    cin >> N;
    
    int i;
    long double n;
    long long int result = 0;
    for(i = 0; i < N; ++i){
        cin >> n;
        result += n * MULTI;
    }
    
    string num;
    num = to_string(result);
    
    for(i = 0; i < num.size(); ++i){
        cout << num[i];
        if(i == num.size() - 11) cout << ".";
    }
    
    return 0;
}