#include <bits/stdc++.h>
using namespace std;
typedef long long ll;

int main() {
    int n;
    cin>>n;
    ll a=0,b=0;
    while (n--) {
        string s;cin>>s;
        int sign=1;
        if (s[0]=='-') {
            sign=-1;
            s=s.substr(1);
        }
        ll c=0,d=0;
        sscanf(s.c_str(),"%lld.%lld",&c,&d);
        while (d!=0&&d<1e9) {
            d*=10;
        }
        a+=c*sign;
        b+=d*sign;
        if (b>=1e10) {
            a++;
            b-=1e10;
        } else if (b<0) {
            a--;
            b+=1e10;
        }
    }
    printf("%lld.%010lld\n",a,b);
    return 0;
}