#include <bits/stdc++.h>
using namespace std;
int main() {
  short i, n;
  string s;
  cin >> s;
  for (i = 1, n = s.size(); i < n - 2; i++)
    if (s[i] == '@')
      if (s[i + 1] != '@' && s[i + 2] != '@')
        s.insert(s.begin() + i + 2, ','), n++;
      else
        break;
  if (s[0] == '@' || s[n - 1] == '@' || i < n - 2)
    cout << "No solution";
  else {
    for (; i >= 0 && s[i] != '@'; i--)
      if (s[i] == ',') {
        s.erase(s.begin() + i);
        break;
      }
    cout << (i >= 0 ? s : "No solution");
  }
  return 0;
}
