#include <bits/stdc++.h>
using namespace std;
int main() {
  char given[300] = {};
  cin >> given;
  int len = strlen(given);
  string Str = "";
  if (given[0] == '@' || given[len - 1] == '@') {
    cout << "No solution" << endl;
    return 0;
  }
  bool ok = true;
  int Count = 0;
  for (int i = 1; i < len - 1;) {
    if (given[i] == '@') {
      Count++;
      if (given[i + 1] != '@' && given[i + 2] != '@') {
        i += 2;
      } else {
        ok = false;
        break;
      }
    } else {
      i++;
    }
  }
  if (ok == true && Count >= 1) {
    for (int i = 0; i < len;) {
      if (given[i] == '@') {
        Str += given[i];
        Str += given[i + 1];
        if (Count > 1) {
          Str += ',';
          Count--;
        }
        i += 2;
      } else {
        Str += given[i];
        i++;
      }
    }
    cout << Str << endl;
  } else {
    cout << "No solution" << endl;
  }
  return 0;
}
