'use strict'

class Main {
  solve() {
    const n = input.nextInt();
    let sum = 0;
    const divisors = Prime.getDivisors(n);
    for (let d of divisors) {
      if (n / d < d - 1) {
        sum += (d-1);
      }
    }
    return sum;
  }
}

class Prime {
  /* 初期化と素数テーブル生成 */
  constructor(n) {
    if (n == null) { n = 1000000; }
    const primeTable = [...((new Array(n)).keys())];
    primeTable[0] = false;
    primeTable[1] = false;
    let max = Math.sqrt(n);
    for(let i = 2;i <= max;++i) {
      if (primeTable[i] !== i) continue;
      for (let j = i * i; j < n; j += i) {
        if (primeTable[j] !== j) continue;
        primeTable[j] = i;
      }
    }
    this.size = n;
    this.primeTable = primeTable;
    this.primeList = primeTable.filter((e,i) => e === i);
  }

  /* テーブルに生成した素数の2乗までの素数判定 */
  isPrime(n) {
    if (n < this.size) return this.primeTable[n] === n;
    let max = Math.sqrt(n);
    for (let i = 0; this.primeList[i] <= max; ++i) {
      if (n % this.primeList[i] === 0) return false;
    }
    return true;
  }

  /* 最小の素因数 */
  getMinimumFactor(n) {
    if (n < this.size) return this.primeTable[n];
    let max = Math.sqrt(n);
    for (let i = 0; this.primeList[i] <= max; ++i) {
      if (n % this.primeList[i] === 0) return this.primeList[i];
    }
    return n;
  }

  /* 素因数の取得
   * 上限: テーブルサイズの二乗*/
  getFactor(n) {
    const ret = [];
    let k = n;
    while(!this.isPrime(k)) {
      const p = this.getMinimumFactor(k)
      ret.push(p);
      k /= p;
    }
    ret.push(k);
    return ret;
  }

  /* 素因数テーブル
   * 上限: テーブルサイズ*/
  getFactorTable(n) {
    const factor = this.getFactor(n);
    const maxFactor = factor[factor.length - 1];
    const ret = [];
    for (let i = 0;this.primeList[i] <= maxFactor; ++i) {
      ret[this.primeList[i]] = 0;
    }
    for (const e of factor) { ++ret[e]; }
    return ret;
  }
  
  /* 約数の個数 */
  getDivisorCount(n) {
    const factor = this.getFactor(n);
    let count = 1;
    let prev = factor[0];
    let factorCount = [];
    for (let i = 1; i < factor.length; ++i) {
      if (factor[i] != prev) {
        factorCount.push(count);
        count = 1;
      }
      else {
        ++count;
      }
      prev = factor[i];
    }
    factorCount.push(count);
    return factorCount.reduce((a,b)=>a * (b+1),1);
  }

  /* 約数の一覧の取得(未ソート) O(√n)*/
  static getDivisors(n) {
    let max = Math.sqrt(n);
    let ret = [];
    if (n % max === 0) {ret.push(max);}
    for(let i = 0; i < max; ++i) {
      if (n % i == 0) {
        ret.push(i);
        ret.push(n / i);
      }
    }
    return ret;
  }
}

const prime = new Prime(1e6);

// console.log(prime.getFactor(3608805));
// console.log(prime.getFactor(59551644));
// console.log(prime.getFactor(490987994));

class Mod {
  constructor(mod) {
    if (mod == null) { mod = Combinatorics.DefaultMod; }
    this.mod = mod;
  }
  mult(a,b) {
    let ret = 0;
    a %= this.mod;
    b %= this.mod;
    while (b) {
      if (b&1) {
        ret += a;
        if (ret > this.mod) { ret -= this.mod; }
      }
      a <<= 1;
      if (a > this.mod) { a -= this.mod; }
      b >>= 1;
    }
    return ret;
  }
  pow(a,b) {
    let ret = 1;
    while(b) {
      if (b&1) { ret = this.mult(ret,a); }
      a = this.mult(a,a);
      b >>= 1;
    }
    return ret;
  }
  div(a,b) { return this.mult(a, this.pow(b, this.mod-2)) }
  comb(n,k) { return MOD.mult(factTable[n],MOD.mult(invFactTable[k],invFactTable[n-k])); }
}
const MOD = new Mod(1e9+7);

class Underscore {
  sum(arr) { return arr.reduce((a,b)=>a+b); }
  modSum(arr,mod) { if (mod == null) { mod = MOD.mod; } return arr.reduce((a,b)=>(a+b)%mod); }
  min(arr, func) { if (func == null) {func = (a,b) => a - b} return arr.reduce((a,b) => func(a,b) < 0 ? a : b); }
  max(arr, func) { if (func == null) {func = (a,b) => a - b} return arr.reduce((a,b) => func(a,b) > 0 ? a : b); }
  sort(arr, func) { if (func == null) {func = (a,b) => a - b} return arr.sort(func) }
  uniq(arr) { 
    arr.sort();
    for(let i = 0; i < arr.length - 1; ++i) { 
      arr[i] = arr[i+1] == arr[i] ? null : arr[i]; 
    }
    return arr.filter(e => e != null);
  }
  range(start, stop, step) {
    if (stop == null) { stop = start || 0; start = 0; }
    if (!step) { step = stop < start ? -1 : 1; }
    const length = Math.max(Math.ceil((stop - start) / step), 0);
    const range = Array(length);
    for (var idx = 0; idx < length; idx++, start += step) { range[idx] = start; }
    return range;
  }
  first (array, n) {
    if (array == null || array.length < 1) return n == null ? void 0 : [];
    if (n == null) return array[0];
    return this.initial(array, array.length - n);
  };
  initial (array, n) { return array.slice.call(array, 0, Math.max(0, array.length - (n == null ? 1 : n))); }
  tail(array, n) { return array.slice.call(array, n == null ? 1 : n); }
  last (array, n) { if (n == null) return array[array.length - 1]; return this.tail(array, Math.max(0, array.length - n)); }
  sumArray (arr) { return this.tail(arr.reduce(((a,b,i) => {a.push(b + a[i]); return a}), [0])); }
  diffArray (arr) { const s = []; for (let i = 1; i < arr.length; ++i) { s.push(arr[i] - arr[i-1]); } return s; }
  // 配列の値以下の最大のindex
  binarySearch (array, key, iteratee) {
    const itr = (obj) => (typeof obj === 'object') ? obj[iteratee] : obj;
    const value = itr(key);
    let low = 0, high = array.length;
    while (low < high) {
      let mid = Math.floor((low + high) / 2);
      if (itr(array[mid]) < value) low = mid + 1; else high = mid;
    }
    return low;
  };
}
const _ = new Underscore();

class Input {
  constructor() {
    this.cursor = 0;
    this.inputAll();
  }

  inputAll() {
    this.data = (require("fs").readFileSync("/dev/stdin", "utf8")).split('\n');
    return this.data;
  }

  /* 1行 or 複数行文字列 */
  nextLine(n) {
    if (n) {
      const ret = this.data.slice(this.cursor, this.cursor + n);
      this.cursor += n;
      return ret;
    }
    return this.data[this.cursor++];
  }
  /* 1整数 */
  nextInt() { return parseInt(this.nextLine()); } 
  /* 一行文字配列 */
  nextStrArr() { return this.nextLine().split(' '); } 
  /* 一行整数配列 */
  nextIntArr() { return this.nextStrArr().map((e) => parseInt(e)); }
  /* 一行浮動小数点配列 */
  nextFloatArr() { return this.nextStrArr().map((e) => parseFloat(e)); }
  /* 複数行整数配列 */
  nextIntLine(n) { return this.nextLine(n).map((e) => parseInt(e)) }
  /* 複数行浮動小数点配列 */
  nextFloatLine(n) { return this.nextLine(n).map((e) => parseFloat(e)) }
  /* 複数行文字列二次元配列 */
  nextStrRange(n) { return this.nextLine(n).map((line) => line.split(' ')); }
  /* 複数行整数二次元配列 */
  nextIntRange(n) {
    return this.nextLine(n).map((line) => line.split(' ').map((e) => parseInt(e)));
  }
  /* 複数行浮動小数点数二次元配列 */
  nextFloatRange(n) {
    return this.nextLine(n).map((line) => line.split(' ').map((e) => parseFloat(e)));
  }
} 
const input = new Input();

class Out {
  constructor() {
    this.option = {
      'true': 'Yes',
      'false': 'No',
    };
  }
  write(output){
    let ret;
    if (output == null) return;
    if (output === true) { ret = this.option['true']; }
    else if (output === false) { ret = this.option['false']; }
    else { ret = output; }
    console.log(ret);
  }
  bool(option) {
    this.option['false'] = option[0];
    this.option['true'] = option[1];
    return this;
  }
}
const out = new Out();

out.write(new Main().solve());


Measured memory_bytes: 60396