#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 n;
vector<string> a[2];
vector<ll> intpart[2], decpart[2];
ll sumint[2], sumdec[2];

bool msign;
ll ansint, ansdec;

int main() {
	cin >> n;
	
	REP(i, n) {
		string str;
		cin >> str;
		if (str[0] == '-') a[1].push_back(str.substr(1));
		else a[0].push_back(str);
	}
	
	ll ten[11];
	ten[0] = 1;
	REP(i, 10) ten[i + 1] = ten[i] * 10;
	
	REP(i, 2) REP(j, a[i].size()) {
		ll nowint = 0, nowdec = 0;
		
		if (a[i][j].find(".") == string::npos)
			nowint = to_ll(a[i][j]);
		else {
			nowint = to_ll(a[i][j].substr(0, a[i][j].find(".")));
			
			string tmp = a[i][j].substr(a[i][j].find(".") + 1);
			nowdec = to_ll(tmp) * ten[10 - tmp.size()];
		}
		
		sumint[i] += nowint;
		sumdec[i] += nowdec;
		
		ll inc = sumdec[i] / 10000000000ll;
		
		sumint[i] += inc;
		sumdec[i] -= inc * 10000000000ll;
	}
	
	if (sumint[0] == sumint[1]) {
		ansint = 0;
		
		if (sumdec[0] < sumdec[1]) msign = true;
		ansdec = abs(sumdec[0] - sumdec[1]);
	}
	else {
		bool f = sumint[0] < sumint[1];
		
		if (sumint[0] < sumint[1]) msign = true;
		
		ansint = sumint[f ^ 0] - sumint[f ^ 1];
		
		if (sumdec[0] < sumdec[1] * (f ? -1 : 1)) {
			ansint--;
			ansdec = 10000000000ll - sumdec[f ^ 1] + sumdec[f ^ 0];
		}
		else ansdec = sumdec[f ^ 0] - sumdec[f ^ 1];
	}
	
	printf("%s%lld.%010lld\n", msign ? "-" : "", ansint, ansdec);
	
	return 0;
}