#include <bits/stdc++.h>
using namespace std;
int main() {
  string a;
  cin >> a;
  vector<int> v;
  for (int i = 0; i < a.length(); i++) {
    if (a[i] == '@') {
      v.push_back(i);
    }
  }
  if (a[0] == '@' or a[a.length() - 1] == '@' or v.size() == 0) {
    cout << "No solution";
    return 0;
  }
  for (int i = 0; i < v.size() - 1; i++) {
    if (v[i + 1] - v[i] <= 2) {
      cout << "No solution";
      return 0;
    }
  }
  for (int i = 0, count = 0; i < a.length(); i++) {
    if (a[i] == '@' and count != v.size() - 1) {
      cout << a[i] << a[i + 1] << ",";
      i++, count++;
    } else {
      cout << a[i];
    }
  }
}
