#include <bits/stdc++.h>
using namespace std;
int main() {
  string s;
  int i, k, g;
  getline(cin, s);
  k = 1;
  g = -1;
  for (i = 0; i < s.length(); i++)
    if (s[i] == '@') {
      g = i;
      if (k > 1)
        k = 0;
      else {
        cout << "No solution";
        return 0;
      }
    } else
      k++;
  if ((g == -1) || (g == s.length() - 1))
    cout << "No solution";
  else
    for (i = 0; i < s.length(); i++) {
      cout << s[i];
      if (s[i] == '@') {
        cout << s[i + 1];
        if (i != g) cout << ',';
        i++;
      }
    }
  return 0;
}
