#include <bits/stdc++.h>
using namespace std;
int n, x, j;
string s, s1, ans;
int main() {
  cin >> s;
  if (s[0] == '@' || s[s.size() - 1] == '@' || s.size() <= 2)
    return printf("No solution"), 0;
  for (int i = 0; i < s.size(); ++i) {
    if (s[i] == '@') n++;
  }
  if (n == 0) return printf("No solution"), 0;
  for (int i = 0; i < s.size(); ++i) {
    if (s[i] != '@') {
      s1 += s[i];
    } else if (s[i] == '@') {
      s1 += s[i];
      if (s[i + 1] == '@')
        return printf("No solution"), 0;
      else
        s1 += s[i + 1];
      s1 += ',';
      if (s1[0] == '@') return printf("No solution"), 0;
      ans += s1;
      s1 = "";
      i++;
    }
    if (i == s.size() - 1 && s1.size() > 0)
      if (s1[0] == '@')
        return printf("No solution"), 0;
      else if (ans[ans.size() - 1] == ',') {
        ans.pop_back();
        ans += s1;
      }
  }
  if (ans[ans.size() - 1] == ',') ans.pop_back();
  cout << ans;
  return 0;
}
