#include <bits/stdc++.h>
using namespace std;
int main() {
  string str;
  cin >> str;
  int n = str.length();
  vector<string> v;
  string s = "";
  int i = 0;
  for (; i < n; i++) {
    if (str[i] == '@') {
      break;
    }
    s += str[i];
  }
  if (s.length() == 0 || i == n) {
    cout << "No solution";
    return 0;
  }
  v.push_back(s);
  v.push_back("@");
  i++;
  s = "";
  for (; i < n; i++) {
    if (str[i] == '@') {
      if (s.length() < 2) {
        cout << "No solution";
        return 0;
      }
      v.push_back(s.substr(0, 1));
      v.push_back(s.substr(1));
      v.push_back("@");
      s = "";
    } else {
      s += str[i];
    }
  }
  if (s.length() == 0) {
    cout << "No solution";
    return 0;
  }
  v.push_back(s);
  int size = v.size();
  cout << v[0] << v[1] << v[2];
  for (int i = 3; i < size - 2; i += 3) {
    cout << "," << v[i] << v[i + 1] << v[i + 2];
  }
  return 0;
}
