#include <bits/stdc++.h>
using namespace std;
int main() {
  string s;
  cin >> s;
  int n = s.size();
  int i = 0, flag = 1, c = 1, last = 0;
  if (s[i] == '@') {
    cout << "No solution";
    return 0;
  } else {
    while (s[i] != '\0') {
      if (s[i] == '@') {
        last = i;
        if (c <= 1) {
          flag = 0;
          break;
        } else {
          c = 0;
        }
      } else {
        c++;
      }
      i++;
    }
    if (flag == 0) {
      cout << "No solution";
      return 0;
    } else if (c == 0) {
      cout << "No solution";
    } else if (last == 0) {
      cout << "No solution";
    } else {
      i = 0;
      while (s[i] != '\0') {
        if (s[i] == '@' && i != last) {
          cout << s[i];
          cout << s[i + 1];
          cout << ",";
          i += 2;
        } else if (i == last) {
          while (s[i] != '\0') {
            cout << s[i];
            i++;
          }
        } else {
          cout << s[i];
          i++;
        }
      }
    }
  }
  return 0;
}
