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

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