#include <algorithm>
#include <cmath>
#include <cstdio>
#include <cstdlib>
#include <functional>
#include <iostream>
#include <iterator>
#include <limits>
#include <list>
#include <map>
#include <numeric>
#include <queue>
#include <set>
#include <sstream>
#include <stack>
#include <string>
#include <utility>
#include <valarray>
#include <vector>

#define N 1000
// #define MOD 1000000007
#define MOD 1000000000000
#define pe(str) return cout<<(str)<<endl,0
#define px(str) {cout<<(str)<<endl;exit(0);}
#define re(i,n) for(int i=0;i<(n);i++)
#define rep(i,a,b) for(int i=(a);i<(b);i++)
#define fe(i,n,f) for_each(i,n,f)
#define bw(a,b,c) (((a)<=(b))&&((b)<=(c)))
using namespace std;

typedef long long ll;
typedef unsigned long long ull;
typedef long double ld;
typedef pair<int,int> pii;

int main(void){
	ll a,b;
	ll k=0,t=0;
	ll n;
	string s;
	cin>>n;
	while(n--){
		cin>>s;
		a=b=0;
		int i=0;
		bool f=false;
		if(s[0]=='-'){i++;f=true;}
		for(;i<s.size()&&s[i]!='.';i++){
			a*=10;
			a+=s[i]-'0';
		}
		int j=0;
		i++;
		for(j=0;i<s.size();i++,j++){
			b*=10;
			b+=s[i]-'0';
		}
		for(;j<10;j++)b*=10;
	if(f)k-=a;else k+=a;
	if(f)t-=b;else t+=b;
	}
	ll gg=10000000000;
	k+=(t/gg);
	t%=gg;
	if(t<0){
		t=-t;
		if(k>=0)k*=-1;
		if(k==0)cout<<'-';
	}
	cout<<k;
	printf(".%010lld",t);
	cout<<endl;
	return 0;
}