#include<bits/stdc++.h>
using namespace std;
string s;
bool flag=true;
int main()
{
	cin>>s;
	for(int i=1;i<=s.size();i++)
	{
		if(s[1]=='@')
		{
			cout<<"No solution";
		}
		if(s[2]=='@'&&s[1]!='@'&&s[3]!='@')
		{
			if(flag==true)
				cout<<s[i-1]<<s[i]<<s[i+1];
			else
				cout<<","<<s[i-1]<<s[i]<<s[i+1];
			flag=false;
			s=s-s[1]-s[2]-s[3];
		}
	}
	if(flag==true)
		cout<<"No solution";
	return 0;
}