#include <bits/stdc++.h>
using namespace std;
string st;
vector<int> pos;
int n, last;
void halt() {
  cout << "No solution" << endl;
  exit(0);
}
int main() {
  getline(cin, st);
  n = st.size();
  if (st.find('@') == -1) halt();
  pos.push_back(-2);
  for (int i = 0; i < n; ++i)
    if (st[i] == '@') pos.push_back(i);
  last = pos.back();
  pos.push_back(n + 1);
  for (int i = 1; i < pos.size(); ++i) {
    if (pos[i] - pos[i - 1] < 3) halt();
  }
  cout << st[0];
  for (int i = 1; i < n; ++i) {
    cout << st[i];
    if (i - 1 != last && st[i - 1] == '@') cout << ",";
  }
  cout << endl;
  return 0;
}
