#include <bits/stdc++.h>
using namespace std;
const long long int INF = 1e18;
const long long int N = 1e5 + 5;
long long int mod = 998244353;
void null() {
  string s;
  cin >> s;
  long long int n = (long long int)s.size();
  vector<long long int> a;
  a.push_back(0);
  long long int cnt = 0;
  for (long long int i = 0; i < n; i++) {
    if (s[i] == '@') {
      a.push_back(i);
      cnt++;
    }
  }
  string z = "No solution";
  if (cnt == 0) {
    cout << z << '\n';
    return;
  }
  a.push_back(n - 1);
  for (int i = 1; i < (long long int)a.size(); i++) {
    if (i == 1 or i == (long long int)a.size() - 1) {
      if (a[i] - a[i - 1] < 1) {
        cout << z << '\n';
        return;
      }
    } else if (a[i] - a[i - 1] <= 2) {
      cout << z << '\n';
      return;
    }
  }
  string ans = "", curr = "";
  long long int cc = 0;
  for (int i = 0; i < n; i++) {
    while (i < n and s[i] != '@') {
      curr += s[i];
      i++;
    }
    cc++;
    curr += '@';
    if (cc != cnt)
      curr += s[i + 1];
    else {
      curr += s.substr(i + 1);
    }
    curr += ',';
    i++;
    ans += curr;
    curr.clear();
    if (cc == cnt) break;
  }
  ans.pop_back();
  cout << ans << '\n';
}
signed main() {
  ios_base::sync_with_stdio(false);
  cin.tie(NULL);
  cout.tie(0);
  cout << setprecision(4);
  cout << fixed;
  long long int t = 1;
  clock_t start, end;
  start = clock();
  while (t--) {
    null();
  }
  end = clock();
  double time_taken = double(end - start) / double(CLOCKS_PER_SEC);
}
