#include <bits/stdc++.h>
using namespace std;
int n;
char s[10000];
vector<string> ans;
int main() {
  cin >> s;
  n = strlen(s);
  if (s[0] == '@' || s[n - 1] == '@') {
    cout << "No solution" << endl;
    return 0;
  }
  bool w = false;
  for (int i = 0; i < n; i++)
    if (s[i] == '@') w = true;
  if (!w) {
    cout << "No solution" << endl;
    return 0;
  }
  ans.clear();
  for (int i = 0; i < n; i++) {
    if (i == 0 || (i > 1 && s[i - 2] == '@')) ans.push_back("");
    ans[ans.size() - 1] += s[i];
  }
  w = false;
  for (int i = 0; i < ans[ans.size() - 1].size(); i++)
    if (ans[ans.size() - 1][i] == '@') w = true;
  if (ans.size() > 1 && !w) {
    ans[ans.size() - 2] += ans[ans.size() - 1];
    ans.pop_back();
  }
  for (int i = 0; i < ans.size(); i++) {
    int cnt = 0;
    for (int j = 0; j < ans[i].size(); j++)
      if (ans[i][j] == '@') cnt++;
    if (cnt > 1) {
      cout << "No solution" << endl;
      return 0;
    }
    if (ans[i][0] == '@' || ans[i][ans[i].size() - 1] == '@') {
      cout << "No solution" << endl;
      return 0;
    }
  }
  for (int i = 0; i < ans.size(); i++) {
    if (i) cout << ',';
    cout << ans[i];
  }
  cout << endl;
  return 0;
}
