import std.stdio, std.conv, std.math, std.string, std.range, std.array,
       std.algorithm;

void main(){
  auto N = readln().strip().to!int();
  long ansi, ansd;
  foreach(immutable int i; 0 .. N) {
    auto t = readln().strip().split('.').map!(to!string)();
    bool minus = false;
    if(t[0][0] == '-') minus = true;
    ansi += t[0].to!long;
    char[] td = "0000000000".dup();
    foreach(ulong j; 0 .. t[1].length) {
      td[j] = t[1][j];
    }
    if(t.length == 2) {
      if(minus) ansd -= td.to!long;
      else ansd += td.to!long;
    }

    //writeln(ansi, ", ", ansd);

    long tt = ansd/(10L^^10);
    ansi += tt;
    ansd -= tt*(10L^^10);
  }

  write(ansi, ".");
  writefln("%010d", ansd);
}