#include <bits/stdc++.h>
using namespace std;
const int INF = 1 << 30;
int main() {
  string s;
  cin >> s;
  string ans = "";
  bool fl = true;
  int prev = -2;
  bool was = false;
  for (int i = 0; i < s.length(); ++i) {
    char c = s[i];
    if (c == '@') {
      if (i - prev <= 2) {
        fl = false;
        break;
      }
      if (was) ans += ",";
      if (!was) {
        was = true;
      }
      for (int j = prev + 2; j <= i; ++j) ans += s[j];
      if (i == s.length() - 1) {
        fl = false;
        break;
      }
      ans += s[i + 1];
      prev = i;
    }
  }
  if (prev == -2) fl = false;
  for (int i = prev + 2; i < s.length(); ++i) ans += s[i];
  if (fl)
    cout << ans;
  else
    cout << "No solution";
  return 0;
}
