#include <bits/stdc++.h>
using namespace std;
const int N = int(2e4 + 5);
const int INF = 1e9 + 7;
string s;
int used[N];
int main() {
  cin >> s;
  int ok = 1, kol = 0;
  for (int i = 0; i < s.size(); ++i) {
    if (s[i] == '@') {
      if (i - 1 >= 0 && s[i - 1] != '@' && !used[i - 1] &&
          i + 1 < (int)s.size() && s[i + 1] != '@' && !used[i + 1]) {
        used[i - 1] = 1;
        used[i + 1] = 1;
      } else {
        ok = 0;
      }
      ++kol;
    }
    if (!ok) {
      break;
    }
  }
  if (!ok || !kol) {
    cout << "No solution\n";
  } else {
    string ans;
    int cur = 0;
    for (int i = 0; i < s.size(); ++i) {
      ans += s[i];
      if (i - 1 >= 0 && s[i - 1] == '@') {
        ++cur;
        if (cur != kol) {
          ans += ',';
        }
      }
    }
    cout << ans;
  }
  return 0;
}
