include [HTML_REMOVED]

include [HTML_REMOVED]

using namespace std;
int main(){
string str;
getline(cin,str);
int a[26]={0};
for(int i=0;i<str.size();i)
a[str[i]-‘a’];
for(int i=0;i<str.size();i++)
if(a[str[i]-‘a’]==1){
cout<<str[i]<<’\n’;
return 0;
}
cout<<”no”;
return 0;
}