#include <bits/stdc++.h>
using namespace std;
int main() {
  ios_base::sync_with_stdio(false);
  cin.tie(NULL);
  cout.tie(NULL);
  ;
  string s;
  cin >> s;
  if (s[0] == '@' || s.back() == '@' || (s.find('@') == -1)) {
    cout << "No solution";
    return 0;
  }
  vector<int> v;
  for (int i = 0; i < s.size(); i++) {
    if (s[i] == '@') v.push_back(i);
  }
  for (int i = 1; i < v.size(); i++) {
    if (v[i] - v[i - 1] < 3) {
      cout << "No solution";
      return 0;
    }
  }
  int pre = 0;
  for (int i = 0; i < v.size(); i++) {
    for (int j = pre; j <= v[i] + 1; j++) {
      cout << s[j];
    }
    if (i + 1 != v.size()) cout << ",";
    pre = v[i] + 2;
  }
  for (int i = pre; i < s.size(); i++) cout << s[i];
  return 0;
}
