include <bits/stdc++.h>

using namespace std; int a[10]={0}; int main() {

//freopen("test.in","r",stdin);
//freopen("test.out","w",stdout);

int n,num1=0,num2=0; cin>>n;

while(n!=0)
{
	int x=n%10;
	n=n/10;
	a[x]++;
}
int flog=0;
for(int i=0;i<=9;i++)
{
	while(a[i]--)
	{
		if(flog==0)
		{
			num1=num1*10+i;flog=1;
		}
		else{
			num2=num2*10+i;flog=0;
		}
	}
}

int h; h=num1+num2; cout<<h; return 0; }