function getBigInt(d) {
  let s = d.toString();
  let dotPos = s.indexOf(".");
  if(dotPos >= 0) {
    const left = s.substr(0, dotPos);
    const right = s.substr(dotPos + 1);
    const zeroNum = 10 - right.length;
    let zero = "";
    for(let i=0; i<zeroNum; i++) zero += "0";
    s = left + right + zero;
  } else {
    for(let i=0; i<10; i++) s += "0";
  }
  return BigInt(s);
}

function addDot(s) {
  s = s.toString();
  const pos = s.length - 10;
  const left = s.substr(0, pos);
  const right = s.substr(pos);
  return left + "." + right;
}

function main(input) {
  const n = Number(input.shift());
  let sum = 0n;
  for(let i=0; i<n; i++) {
    sum += getBigInt(input[i]);
  }
  console.log(addDot(sum));
}

main(require("fs").readFileSync("/dev/stdin", "utf8").trim().split("\n"));