function main(input) {
  let N = BigInt(input.shift());
  let sum = 0n;
  for(let i=1n; i*i<=N; i++) {
    if(N % i == 0n) {
      sum += i;
      sum += N / i;
    }
  }
  console.log(sum.toString());
}

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