#include <bits/stdc++.h>
using namespace std;
long long in() {
  int32_t x;
  scanf("%d", &x);
  return x;
}
const long long maxn = 1e6 + 10;
int32_t main() {
  string a = "";
  string s;
  cin >> s;
  vector<string> ans;
  for (long long i = 0; i < s.size(); i++) {
    if (s[i] == '@') {
      if (a.empty() || i + 1 == s.size() || s[i + 1] == '@')
        return cout << "No solution" << endl, 0;
      a += '@';
      a += s[i + 1];
      ans.push_back(a);
      a = "";
      i++;
    } else
      a += s[i];
  }
  if (!ans.size()) return cout << "No solution" << endl, 0;
  ans.back() += a;
  for (long long i = 0; i < ans.size(); i++) {
    if (i) cout << ",";
    cout << ans[i];
  }
}
