#include <bits/stdc++.h>
using namespace std;
signed main() {
  ios_base::sync_with_stdio(false);
  cin.tie(0);
  cout.tie(0);
  string s;
  cin >> s;
  long long int n = (long long int)s.size();
  if (s[0] == '@' || s[n - 1] == '@') {
    cout << "No solution";
    return 0;
  }
  long long int flag = 0;
  for (long long int i = 0; i < n; i++) {
    if (s[i] == '@') {
      flag = 1;
      for (long long int j = i + 1; j < n; j++) {
        if (s[j] == '@') {
          if (j - i <= 2) {
            cout << "No solution";
            return 0;
          }
          i = j - 1;
          break;
        }
      }
    }
  }
  if (flag == 0) {
    cout << "No solution";
    return 0;
  }
  long long int pos = 0;
  for (long long int i = 0; i < n; i++) {
    if (s[i] != '@') cout << s[i];
    if (s[i] == '@') {
      pos = i;
      break;
    }
  }
  for (long long int i = pos; i < n - 1; i++) {
    if (s[i + 1] != '@')
      cout << s[i];
    else {
      cout << ',';
      cout << s[i];
    }
  }
  cout << s[n - 1];
}
