#include <bits/stdc++.h>
using namespace std;
void solve() {
  string str;
  cin >> str;
  long long int count = 0;
  vector<string> vect;
  long long int i = 0;
  for (i = str.length() - 1; i >= 0; i--)
    if (str[i] == '@') break;
  if (i == -1) {
    cout << "No solution";
    return;
  }
  for (i = 0; i < str.length(); i++) {
    string well = "";
    if (count == 0) {
      if (str[i] == '@') {
        cout << "No solution";
        return;
      }
      while (i < str.length()) {
        if (str[i] == '@') {
          if (i == str.length() - 1 || str[i + 1] == '@') {
            cout << "No solution";
            return;
          }
          well = well + '@';
          well = well + str[(i++) + 1];
          vect.push_back(well);
          count = 0;
          break;
        }
        well = well + str[i++];
      }
    }
  }
  for (i = 0; i < vect.size() - 1; i++) cout << vect[i] << ",";
  cout << vect[vect.size() - 1];
  for (i = str.length() - 1; i >= 0; i--)
    if (str[i] == '@') break;
  for (long long int j = i + 2; j < str.length(); j++) cout << str[j];
}
int main() {
  long long int test = 1;
  while (test--) solve();
}
