#include <bits/stdc++.h>
using namespace std;
const int MAGIC_NUMBER = 400005;
const int MN = 200004;
using dint = uint64_t;
dint INF = 10000;
void readData();
void printState();
void answerReqs();
int main() {
  readData();
  answerReqs();
}
void printState() { cout << "No solution" << endl; }
vector<string> vec;
void answerReqs() {
  if (vec.size() < 2 || vec.front().length() < 1) {
    printState();
    return;
  }
  if (vec.back().length() < 1) {
    printState();
    return;
  }
  for (int i = 1; i < vec.size() - 1; ++i) {
    if (vec[i].length() < 2) {
      printState();
      return;
    }
  }
  cout << vec[0];
  for (int i = 1; i < vec.size() - 1; ++i) {
    cout << '@';
    cout << vec[i][0] << ',' << vec[i].substr(1);
  }
  cout << '@' << vec.back();
}
void readData() {
  ios_base::sync_with_stdio(false);
  cin.tie(NULL);
  stringstream out;
  string s;
  cin >> s;
  for (auto &c : s) {
    if (c == '@') {
      vec.emplace_back(out.str());
      out.str("");
      continue;
    }
    out << c;
  }
  vec.emplace_back(out.str());
}
