#include <bits/stdc++.h>
using namespace std;
int main() {
  string s;
  cin >> s;
  string ans = "", mail = "";
  bool check = false, arroba = false;
  for (int i = 0; s[i]; i++) {
    mail += s[i];
    if (s[i] == '@') {
      arroba = true;
      if (check) return cout << "No solution", 0;
      if (mail.size() == 1) return cout << "No solution", 0;
      check = true;
    } else if (check) {
      check = false;
      mail += ",";
      ans += mail;
      mail = "";
    }
  }
  if (ans.back() == ',') ans.erase(ans.begin() + ans.size() - 1);
  ans += mail;
  if (check || !arroba) return cout << "No solution", 0;
  cout << ans;
}
