var GET=(function(){function f(s){return new g(s);}function g(s){this._s=s.trim().split("\n");this._y=0;}g.prototype.a=function(f){var s=this._s, y=this._y, r;if(typeof s[y]==="string")s[y]=s[y].split(" ").reverse();r=s[y].pop();if(!s[y].length)this._y++;return f?r:+r;};g.prototype.l=function(f){var s=this._s[this._y++].split(" ");return f?s:s.map(a=>+a);};g.prototype.m=function(n,f){var r=this._s.slice(this._y,this._y+=n).map(a=>a.split(" "));return f?r:r.map(a=>a.map(a=>+a));};g.prototype.r=function(n,f){var r=this._s.slice(this._y,this._y+=n);return f?r:r.map(a=>+a);};return f;})();
var o=GET(require("fs").readFileSync("/dev/stdin","utf8"));
function xArray(v){var a=arguments,l=a.length,r="Array(a["+--l+"]).fill(0).map(x=>{return "+v+";})";while(--l)r="Array(a["+l+"]).fill(0).map(x=>"+r+")";return eval(r);}

console.log(main());
function main(){
  var n = o.a();
  var q = n;
  if(n < 3)return 0;
  var ans = 0;
  var set = new Set();
  set.add(1);
  for(var i = 2; i*i <= n; i++){
    while(n%i === 0){
      var set2 = new Set()
      for(var j of set){
        set2.add(j);
        set2.add(j*i);
      }
      set = set2;
      n /= i;
    }
  }
  if(n > 1){
    var set2 = new Set()
    for(var j of set){
      set2.add(j);
      set2.add(j*n);
    }
    set = set2;
  }
  for(var j of set){
    j--;
    if(Math.floor(q/j) === q%j)ans += j;
  }
  return ans;
}