#include <bits/stdc++.h>
using namespace std;
int main() {
  string input;
  string answer = "";
  cin >> input;
  bool ok = true;
  bool added = false;
  while (input.length() > 0) {
    if (input.find("@") == -1) {
      if (!added)
        ok = false;
      else
        answer = answer.substr(0, answer.length() - 1) + input + ",";
      break;
    }
    if (input[0] == '@') {
      ok = false;
      break;
    }
    if (input[input.size() - 1] == '@') {
      ok = false;
      break;
    }
    if (input[input.find("@") + 1] == '@') {
      ok = false;
      break;
    }
    answer = answer + input.substr(0, input.find("@") + 2);
    answer = answer + ",";
    input = input.substr(input.find("@") + 2, input.length());
    added = true;
  }
  if (ok)
    cout << answer.substr(0, answer.length() - 1) << endl;
  else
    cout << "No solution" << endl;
  return 0;
}
