#include <bits/stdc++.h>
using namespace std;
int main() {
  std::ios::sync_with_stdio(false);
  string s;
  cin >> s;
  std::vector<int> ats;
  for (int i = 0; i < s.size(); i++)
    if (s[i] == '@') ats.push_back(i);
  if (ats.size() == 0) {
    cout << "No solution";
    return 0;
  }
  if (ats[0] == 0 || ats[ats.size() - 1] == s.size() - 1) {
    cout << "No solution";
    return 0;
  }
  for (int i = 1; i < ats.size(); i++)
    if (ats[i] - ats[i - 1] <= 2) {
      cout << "No solution";
      return 0;
    }
  int st = 0;
  for (int i = 0; i < ats.size(); i++) {
    cout << s.substr(st, ats[i] - st) << "@" << s[ats[i] + 1];
    st = ats[i] + 2;
    if (i != ats.size() - 1)
      cout << ',';
    else
      cout << s.substr(st);
  }
}
