#include <bits/stdc++.h>
using namespace std;
int main() {
  string s, tmp = "";
  cin >> s;
  vector<string> mail;
  int last;
  for (int i = 0; i < s.size(); ++i)
    if (s[i] == '@') {
      if (tmp == "") {
        puts("No solution");
        return 0;
      }
      last = i;
      if (i < s.size() - 1 && s[i + 1] != '@') {
        ++i, tmp += '@', tmp += s[i];
        mail.push_back(tmp);
        tmp = "";
      } else {
        puts("No solution");
        return 0;
      }
    } else
      tmp += s[i];
  if (mail.size() == 0) {
    puts("No solution");
    return 0;
  }
  for (int i = last + 2; i < s.size(); ++i) mail.back() += s[i];
  for (int i = 0; i < mail.size() - 1; ++i) cout << mail[i] << ",";
  cout << mail.back();
}
