#include <bits/stdc++.h>

using namespace std;

#define FOR(i,a,b) for(int i=(a);i<(b);i++)
#define REP(i,n) FOR(i,0,n)
#define ALL(v) (v).begin(),(v).end()

template<typename A, typename B> inline bool chmax(A &a, B b) { if (a<b) { a=b; return 1; } return 0; }
template<typename A, typename B> inline bool chmin(A &a, B b) { if (a>b) { a=b; return 1; } return 0; }

typedef unsigned long long ull;
typedef long long ll;
typedef pair<int, int> pii;
typedef pair<ll, ll> pll;
typedef pair<int, pii> P;

const ll INF = 1ll<<29;
const ll MOD = 1000000007;
const double EPS  = 1e-10;

ll to_ll(string str) {
	stringstream ss(str);
	ll res;
	ss >> res;
	return res;
}

int main() {
	int n;
	cin >> n;
	
	ll intpart = 0, decpart = 0;
	
	ll ten[11];
	ten[0] = 1;
	REP(i, 10) ten[i + 1] = ten[i] * 10;
	
	REP(i, n) {
		string str;
		cin >> str;
		
		ll nint = 0, ndec = 0;
		
		if (str.find(".") == string::npos)
			nint = to_ll(str);
		else {
			nint = to_ll(str.substr(0, str.find(".")));
			
			bool minus = str[0] == '-';
			string tmp = str.substr(str.find(".") + 1);
			
			ndec = to_ll(tmp) * (minus ? -1 : 1) * ten[10 - tmp.size()];
		}
		
		intpart += nint;
		decpart += ndec;
		
		ll inc = decpart / 10000000000ll;
		
		intpart += inc;
		decpart -= inc * 10000000000ll;
	}
	
	printf("%lld.%010lld\n", intpart, decpart);
	
	return 0;
}