#include <bits/stdc++.h>
using namespace std;
int main() {
  string str, test = "", finl = "";
  int i, flag = 0;
  cin >> str;
  for (i = 0; i < str.length(); ++i) {
    if (flag == 2 && str[i + 1] == '@') {
      flag = 0;
      i--;
      finl += ",";
    } else if ((flag == 0 && str[i] == '@') ||
               (flag == 1 && str[i] == '@' && str[i + 2] == '@') ||
               (flag == 2 && str[i] == '@')) {
      cout << "No solution";
      return 0;
    } else if (flag == 1 && str[i] == '@') {
      finl += str[i];
      flag = 2;
    } else {
      finl += str[i];
      if (flag == 0) flag = 1;
    }
  }
  if (finl.find('@') == -1 || finl[finl.length() - 1] == '@')
    cout << "No solution";
  else
    cout << finl;
  return 0;
}
