#include <bits/stdc++.h>
using namespace std;
int main() {
  string a;
  cin >> a;
  vector<int> attherates;
  vector<pair<int, int> > lists;
  int i = 0;
  while (i < (int)a.length()) {
    if (a[i] == '@') {
      attherates.push_back(i);
      if (i == 0 || i == (int)a.length() - 1) {
        cout << "No solution";
        return 0;
      } else if (((int)attherates.size() > 1) &&
                 (attherates[(int)attherates.size() - 1] -
                      attherates[(int)attherates.size() - 2] <
                  3)) {
        cout << "No solution";
        return 0;
      }
    }
    i++;
  }
  if ((int)attherates.size() == 0) {
    cout << "No solution";
    return 0;
  } else if ((int)attherates.size() == 1) {
    lists.push_back(make_pair(0, (int)a.length() - 1));
  } else {
    int l = 0;
    int j = 0;
    while (j < (int)attherates.size() - 1) {
      lists.push_back(make_pair(l, attherates[j] + 1));
      l = attherates[j] + 2;
      j++;
    }
    lists.push_back(make_pair(l, (int)a.length() - 1));
  }
  int vis = 0;
  while (vis < (int)lists.size()) {
    if (vis != 0) {
      cout << ",";
    }
    int abc = lists[vis].first;
    while (abc <= lists[vis].second) {
      cout << a[abc];
      abc++;
    }
    vis++;
  }
  return 0;
}
