1 #define mm(a) memset(a,0,sizeof(a));
 2 #define max(x,y) (x)>(y)?(x):(y)
 3 #define min(x,y) (x)<(y)?(x):(y)
 4 #define Fopen freopen("1.in","r",stdin); freopen("m.out","w",stdout);
 5 #define rep(i,a,b) for(int i=(a);i<=(b);i++)
 6 #define per(i,b,a) for(int i=(b);i>=(a);i--)
 7 #include<bits/stdc++.h>
 8 typedef long long ll;
 9 #define PII pair<ll,ll>
10 using namespace std;
11 const int INF=0x3f3f3f3f;
12 const int MAXN=(int)2e5 + 5;
13 const ll mod=1e9+7;
14 
15 char s[MAXN];
16 int a,b,c;
17 int main() {
18     scanf("%s",s);
19     for(int i=0; s[i]; i++)
20         if(s[i]=='a')a++;
21         else if(s[i]=='b')b++;
22         else c++;
23     for(int i=1;i<=a;i++)printf("a");
24     for(int i=1;i<=b;i++)printf("b");
25     for(int i=1;i<=c;i++)printf("c");
26     printf("\n");
27     return 0;
28 }