#include <bits/stdc++.h>
using namespace std;
map<string, long long int> mp;
bool comp(pair<long long int, string>& a, pair<long long int, string>& b) {
  if (a.first != b.first)
    return a.first > b.first;
  else
    return a.second < b.second;
}
long long int solve() {
  string s;
  cin >> s;
  long long int n = s.length(), i;
  long long int pre = -10;
  for (i = 0; i < n; i++) {
    if (s[i] == '@') {
      if (i - pre < 3) {
        cout << "No solution";
        return 0;
      }
      pre = i;
    }
  }
  if (s[0] == '@' || s[n - 1] == '@') {
    cout << "No solution";
    return 0;
  }
  long long int j = n - 1;
  while (j >= 0 && s[j] != '@') j--;
  if (j == -1) {
    cout << "No solution";
    return 0;
  }
  for (i = 0; i < j; i++) {
    cout << s[i];
    if (i - 1 >= 0 && s[i - 1] == '@') cout << ',';
  }
  while (j < n) cout << s[j++];
}
signed main() {
  long long int t = 1;
  while (t--) solve();
}
