#include <bits/stdc++.h>
using namespace std;
queue<int> qu;
queue<char> q;
int main() {
  string s;
  int len, i, tag, a, b, f;
  while (cin >> s) {
    while (!qu.empty()) qu.pop();
    while (!qu.empty()) q.pop();
    len = s.length();
    for (i = 0; i < len; i++) {
      if (s[i] == '@') qu.push(i);
    }
    if (qu.empty())
      cout << "No solution" << endl;
    else {
      a = qu.front();
      qu.pop();
      if (a == 0)
        cout << "No solution" << endl;
      else {
        tag = 1;
        f = 0;
        while (!qu.empty()) {
          b = qu.front();
          qu.pop();
          if (b - a < 3) {
            tag = 0;
            break;
          } else {
            for (i = f; i <= a + 1; i++) q.push(s[i]);
            q.push(',');
            f = a + 2;
            a = b;
          }
        }
        if (tag == 0)
          cout << "No solution" << endl;
        else {
          if (a == len - 1)
            cout << "No solution" << endl;
          else {
            while (!q.empty()) {
              cout << q.front();
              q.pop();
            }
            for (i = f; i < len; i++) cout << s[i];
            cout << endl;
          }
        }
      }
    }
  }
  return 0;
}
