#include<bits/stdc++.h>
using namespace std;
#define inf 1000000000
#define INF 1000000000000000
#define ll long long
#define ull unsigned long long
#define M (int)(1e9+7)
#define P pair<int,int>
#define PLL pair<ll,ll>
#define FOR(i,m,n) for(int i=(int)m;i<(int)n;i++)
#define RFOR(i,m,n) for(int i=(int)m;i>=(int)n;i--)
#define rep(i,n) FOR(i,0,n)
#define rrep(i,n) RFOR(i,n,0)
#define all(a) a.begin(),a.end()
#define IN(a,n) rep(i,n){ cin>>a[i]; }
const int vx[4] = {0,1,0,-1};
const int vy[4] = {1,0,-1,0};
#define PI 3.14159265
#define F first
#define S second
#define PB push_back
#define EB emplace_back
#define int ll
#define vi vector<int>


main(){
  cin.tie(0);
  ios::sync_with_stdio(false);

  int m;
  int a=0,b=0;
  cin>>m;
  while(m--){
    string s;
    cin>>s;
    string n="";
    int i=0;
    bool mi=false;
    if(s[i]=='-'){
      mi=true;
      i++;
    }
    while(i<s.size()&&s[i]!='.'){
      n+=s[i];
      i++;
    }

    i++;

    int j=1;
    while(!n.empty()){
      if(mi){
        a-=j*(n[n.size()-1]-'0');
      }else{
        a+=j*(n[n.size()-1]-'0');
      }
      j*=10;
      n.erase(n.end()-1);
    }

    while(i<s.size()){
      n+=s[i];
      i++;
    }
    while(n.size()<10) n+='0';
    //cout<<' '<<n<<endl;
    j=1;
    while(!n.empty()){
      if(mi){
        b-=j*(n[n.size()-1]-'0');
      }else{
        b+=j*(n[n.size()-1]-'0');
      }
      j*=10;
      n.erase(n.end()-1);
    }
    //cout<<b<<endl;
    if(b<0){
      a--;
      b+=(int)1e10;
    }if(b>=(int)1e10){
      a++;
      b-=(int)1e10;
    }
    //cout<<a<<' '<<b<<endl;
  }

  printf("%lld.%010lld\n",a,b);
}