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