#include <bits/stdc++.h>
using namespace std;
void solutionB();
int main() {
  ios_base::sync_with_stdio(false);
  solutionB();
  return EXIT_SUCCESS;
}
string s;
void solve() {
  vector<string> ans;
  string word;
  for (long long i = 0; i < s.size(); ++i) {
    if (s[i] == '@') {
      if (i == s.size() - 1 || word.empty() || word[0] == '@' ||
          s[i + 1] == '@') {
        cout << "No solution" << endl;
        return;
      }
      word += s.substr(i, 2);
      ans.push_back(word);
      word = "";
      ++i;
    } else {
      word += s[i];
    }
  }
  if (!word.empty()) {
    if (ans.empty()) {
      cout << "No solution" << endl;
      return;
    }
    ans.back() += word;
  }
  for (long long i = 0; i < ans.size(); ++i) {
    if (i) cout << ",";
    cout << ans[i];
  }
  cout << endl;
}
void solutionB() {
  for (; cin >> s;) {
    solve();
    cerr << endl;
  }
}
