#include <bits/stdc++.h>
using namespace std;
int main() {
  string s;
  cin >> s;
  int len = s.length();
  if (s[0] == '@' || s[len - 1] == '@' || s.find('@') == string::npos) {
    cout << "No solution";
    return 0;
  }
  int i = 0, j = 0;
  int* a = new int[100];
  a[j++] = -1;
  while (i != len) {
    if (s[i] == '@') a[j++] = i;
    i++;
  }
  a[j++] = len;
  for (i = 1; i < j - 2; i++)
    if (a[i + 1] - a[i] - 1 < 2) {
      cout << "No solution";
      return 0;
    }
  cout << s.substr(0, a[1]);
  for (i = 1; i < j - 2; i++) {
    cout << '@' << s[a[i] + 1] << ","
         << s.substr(a[i] + 2, a[i + 1] - a[i] - 2);
  }
  cout << "@" << s.substr(a[j - 2] + 1, a[j - 1] - a[j - 2] - 1);
  return 0;
}
