#include <bits/stdc++.h>
using namespace std;
int main() {
  string s;
  cin >> s;
  int ps = -1;
  if (s[0] == '@') {
    cout << "No solution" << endl;
    return 0;
  }
  int n = s.size();
  for (int i = 1; i < n; i++) {
    if (s[i] == '@') {
      if (ps == -1)
        ps = i;
      else if (i - ps <= 2) {
        cout << "No solution" << endl;
        return 0;
      } else
        ps = i;
    }
  }
  if (ps == -1 || ps == n - 1) {
    cout << "No solution" << endl;
    return 0;
  }
  for (int i = 0; i < n; i++) {
    cout << s[i];
    if (i - 1 >= 0 && s[i - 1] == '@' && i < ps) cout << ",";
  }
  return 0;
}
