#include <bits/stdc++.h>
using namespace std;
int main() {
  string s, ans = "";
  cin >> s;
  int len = s.length(), i;
  if (s[0] == '@' || s[len - 1] == '@') {
    cout << "No solution" << endl;
    return 0;
  }
  ans += s[0];
  char ant = s[0];
  for (i = 1; i < len; ++i) {
    if (s[i] == '@') {
      if (ant == '@' || ant == ',') break;
      if (i + 1 < len && s[i + 1] != '@') {
        ans += s[i];
        ans += s[i + 1];
        if (s.substr(i + 1).find("@") != string::npos) {
          ans += ",";
          ant = ',';
        } else
          ant = s[i + 1];
        i++;
      } else
        break;
    } else {
      ans += s[i];
      ant = s[i];
    }
  }
  if (i >= len && (ans.find("@") != string::npos)) {
    if (ans[ans.length() - 1] == ',')
      cout << ans.substr(0, ans.length() - 1) << endl;
    else
      cout << ans << endl;
  } else
    cout << "No solution" << endl;
  return 0;
}
