import std.string, std.stdio, std.algorithm, std.container, std.typecons, std.conv;

void main(){
    int n;
    scanf("%d", &n);
    readln;

    int[] ans = new int[24];
    foreach(i; 0..n){
        string s = readln.chomp;
        auto ss = s.split('.');
        if(s.length == 1){
            ss ~= "0";
        }
        int sign = ss[0][0] == '-' ? -1 : +1;
        ss[0] = ss[0].replace("-", "0");
        while(ss[0].length < 12) ss[0] = "0" ~ ss[0];
        while(ss[1].length < 12) ss[1] ~= "0";
        string x = ss[0] ~ ss[1];
        foreach(j; 0..24){
            ans[j] += sign * (x[j] - '0');
        }
    }
    foreach_reverse(i; 1..24){
        while(ans[i] >= 10){
            ans[i] -= 10;
            ans[i-1] += 1;
        }
        while(ans[i] < 0){
            ans[i] += 10;
            ans[i-1] -= 1;
        }
    }
    int sign = ans[0] < 0 ? -1 : +1;
    foreach(i; 0..24) ans[i] *= sign;
    foreach_reverse(i; 1..24){
        while(ans[i] >= 10){
            ans[i] -= 10;
            ans[i-1] += 1;
        }
        while(ans[i] < 0){
            ans[i] += 10;
            ans[i-1] -= 1;
        }
    }
    // writeln(ans);
    ans = ans[2..22];
    // writeln(ans);
    auto pos = ans[0..10], neg = ans[10..$];
    while(pos.length > 1 && pos[0] == 0){
        pos = pos[1..$];
    }
    if(sign < 0) write("-");
    write(pos.map!(to!string).join);
    write(".");
    writeln(neg.map!(to!string).join);
}