#include <bits/stdc++.h>

#define rep(i,n) for(int i=0;i<(n);i++)

using namespace std;
using lint=long long;

int main(){
	int n; scanf("%d",&n);
	vector<lint> a(n),b(n);
	rep(i,n){
		string s; cin>>s;
		if(count(s.begin(),s.end(),'.')==0) s+='.';
		int pos=find(s.begin(),s.end(),'.')-s.begin();
		s+=string(11-(s.length()-pos),'0');

		if(s[0]!='-'){
			a[i]=stoll(s.substr(0,pos));
			b[i]=stoll(s.substr(pos+1));
		}
		else{
			a[i]=stoll(s.substr(0,pos))-1;
			b[i]=10000000000LL-stoll(s.substr(pos+1));
		}
	}

	lint ans1=0,ans2=0;
	rep(i,n){
		ans1+=a[i];
		ans2+=b[i];
	}
	printf("%lld.%010lld\n",ans1+ans2/10000000000LL,ans2%10000000000LL);

	return 0;
}