#include <bits/stdc++.h>
using namespace std;
pair<pair<int, int>, int> pii[123456];
string s;
int main() {
  cin >> s;
  bool flag = 0;
  if (s[0] == '@' || s[s.size() - 1] == '@') {
    flag = 1;
  }
  int k = 0;
  for (int i = 1; s[i]; i++) {
    if (s[i] == '@') {
      k = 1;
    }
    if (s[i] == '@' && (s[i - 1] == '@' || (i > 1 && s[i - 2] == '@'))) {
      flag = 1;
      cout << "No solution" << endl;
      exit(0);
    }
  }
  if (flag == 1 || k == 0) {
    cout << "No solution" << endl;
    exit(0);
  }
  for (int i = 0; s[i]; i++) {
    cout << s[i];
    if (s[i] == '@') flag = 1;
    if (flag == 1 && s[i + 2] == '@') {
      cout << ",";
    }
  }
  cout << endl;
}
