#include <bits/stdc++.h>
using namespace std;
int main() {
  string s;
  cin >> s;
  vector<string> ans;
  string email = "";
  bool isPoss = true;
  for (int i = 0; i < s.length(); i++) {
    if (s[i] == '@') {
      if ((i + 1 < s.length()) && (s[i + 1] != '@')) {
        if (email == "") {
          isPoss = false;
          break;
        } else {
          email += s[i];
          email += s[i + 1];
          ans.push_back(email);
          i++;
          email = "";
        }
      } else {
        isPoss = false;
        break;
      }
    } else {
      email += s[i];
    }
  }
  if ((email != "") && (isPoss) && (ans.size() > 0)) {
    ans[ans.size() - 1] = ans[ans.size() - 1] + email;
  }
  if ((ans.size() == 0) || (!isPoss)) {
    cout << "No solution";
  } else {
    cout << ans[0];
    for (int i = 1; i < ans.size(); i++) {
      cout << "," << ans[i];
    }
  }
}
