#include <bits/stdc++.h>
using namespace std;
long long rPow(long long n, long long k) {
  if (k <= 0) return 1;
  return n * rPow(n, --k);
}
int main() {
  ios::sync_with_stdio(0);
  cin.tie();
  cout.tie();
  string s;
  cin >> s;
  string res = "";
  if (s[0] == '@') return cout << "No solution" << endl, 0;
  for (int i = 0; i < s.size(); i++) {
    if (s[i] != '@')
      res += s[i];
    else {
      if (i < s.size() - 1 && s[i + 1] == '@')
        return cout << "No solution" << endl, 0;
      else if (i < s.size() - 2 && s[i + 1] != '@' && s[i + 2] == '@')
        return cout << "No solution" << endl, 0;
      else if (i == s.size() - 1)
        return cout << "No solution" << endl, 0;
      else {
        for (int k = i; k < s.size(); k++) {
          if (k < s.size() - 1 && s[k + 1] == '@') {
            res += ',';
            i = k - 1;
            break;
          } else {
            res += s[k];
            i = k;
          }
        }
      }
    }
  }
  for (int i = 0; i < res.size(); i++)
    if (res[i] == '@') return cout << res << endl, 0;
  return cout << "No solution" << endl, 0;
  return 0;
}
