#define _USE_MATH_DEFINES

#include <iostream>
#include <iomanip>

#include <algorithm>
#include <cmath>

#include <string>
#include <list>
#include <queue>
#include <vector>
#include <complex>
#include <set>

/////////
#define REP(i, x, n) for(int i = x; i < n; i++)
#define rep(i,n) REP(i,0,n)
#define P(p) cout<<(p)<<endl;
/////////
typedef long long LL;
typedef long double LD;
/////////
using namespace::std;
/////////
const LL kmul = 10000000000;

void add0(LL num){
	LL keta = 10;
	int count = 1;
	while(num >= keta){
		keta *= 10;
		++count;
	}
	for(int i=10-count;i>0;--i){
		cout<<'0';
	}
}

int main(void){
    std::cin.tie(0);
    std::ios::sync_with_stdio(false);
    std::cout << std::fixed;//
    //cout << setprecision(11);//
	
	int N;
	cin>>N;

	string A[100];
	rep(i,N){
		cin>>A[i];
	}

	LL H[100],L[100];
	rep(i,100){
		H[i]=0;
		L[i]=0;
	}
	int nflag = 1;
	int hl = 0;
	unsigned int k=0;
	LL Lmul;
	rep(i,N){
		if(A[i][0]=='-'){
			nflag = -1;
			k=1;
		}
		else{
			nflag = 1;
			k=0;
		}
		hl = 0;
		Lmul = kmul;
		for(;k<A[i].size();++k){
			if(A[i][k] == '.'){
				++hl;
				Lmul /= 10;
			}
			else if(hl==0){
				H[i] = H[i]*10 + A[i][k] - '0';
			}
			else{
				L[i] = L[i] + (A[i][k]-'0') * Lmul;
				Lmul /= 10;
			}
		}
		H[i] = nflag*H[i];
		L[i] = nflag*L[i];
	}

	LL Hans=0,Lans=0;
	rep(i,N){
		Lans += L[i];
		Hans += H[i] + Lans/kmul;
		Lans -= (Lans/kmul)*kmul;
		if(Hans > 0 && Lans<0){
			Hans -= 1;
			Lans = kmul + Lans;
		}
		else if( Hans < 0 && Lans > 0){
			Hans += 1;
			Lans = -kmul + Lans;
		}
	}

	if(Hans == 0){
		if(Lans < 0){
			cout << '-';
			Lans *= -1;
		}
	}
	else if(Hans < 0 && Lans < 0){
		Lans *= -1;
	}
	cout << Hans << '.';
	add0(Lans);
	cout << Lans << endl;

	return 0;
}