#include <iostream>
using namespace std;
#include <string>
int main() {
  int a;
  cin>>a;
  string s1,s2,s3;
  string s;
  cin>>s;
  for(char c:s){
    if(c>='a'&&c<='z')s1+=c;
    else if(c>='0'&&c<='9')s2+=c;
    else s3+=c;
  }
  cout<<s1+s2+s3<<endl;
  return 0;
}
// 64 位输出请用 printf("%lld")