#include <bits/stdc++.h>
using namespace std;
vector<string> ans;
bool check(string &email) {
  if (email.length() < 2) return 0;
  if (email[0] == '@') return 0;
  bool was_dog = 0;
  for (int i = 1; i < email.length() - 1; i++) {
    if (email[i] == '@' && was_dog) return 0;
    if (email[i] == '@') was_dog = 1;
  }
  if (email.back() == '@') return 0;
  if (!was_dog) return 0;
  return 1;
}
int main() {
  string s;
  cin >> s;
  for (int i = 1; i < s.length(); i++) {
    if (s[i] == s[i - 1] && s[i] == '@') {
      cout << "No solution";
      return 0;
    }
  }
  if (s.back() == '@' || s[0] == '@') {
    cout << "No solution";
    return 0;
  }
  string a = "";
  for (int i = 0; i < s.length(); i++) {
    if (s[i] != '@') {
      a += s[i];
      continue;
    }
    a += s[i];
    a += s[i + 1];
    ans.push_back(a);
    a = "";
    i++;
  }
  if (ans.size()) ans.back() += a;
  for (int i = 0; i < ans.size(); i++) {
    if (!check(ans[i])) {
      cout << "No solution";
      return 0;
    }
  }
  if (ans.size() == 0) {
    cout << "No solution";
    return 0;
  }
  for (int i = 0; i < ans.size(); i++) {
    cout << ans[i];
    if (i != ans.size() - 1) cout << ",";
  }
  return 0;
}
