#include <bits/stdc++.h>
using namespace std;
int main() {
  string str;
  vector<string> l;
  bool a, m;
  int beg = 0, i, sum = 0;
  cin >> str;
  a = false;
  m = false;
  for (i = 0; i < str.size(); i++)
    if (str[i] == '@') sum++;
  for (i = 0; i < str.size(); i++) {
    if (str[i] == '@' && !m && a) {
      m = true;
      sum--;
      continue;
    } else if (str[i] == '@')
      break;
    if (!a)
      a = true;
    else if (m) {
      string tmp;
      if (sum)
        tmp = str.substr(beg, i - beg + 1);
      else
        tmp = str.substr(beg);
      l.push_back(tmp);
      beg = i + 1;
      m = false;
      a = false;
    }
  }
  if (i < str.size())
    printf("No solution\n");
  else if (i == str.size() && m)
    printf("No solution\n");
  else if (l.size() == 0)
    printf("No solution\n");
  else {
    for (i = 0; i < l.size() - 1; i++) cout << l[i] << ',';
    cout << l[l.size() - 1] << endl;
  }
  return 0;
}
