#include <bits/stdc++.h>
using namespace std;
int main() {
  string str;
  cin >> str;
  int c = 0;
  for (int j = 0; j < str.length(); j++) {
    if (str[j] == '@') {
      c = c + 1;
    }
  }
  if (c == 0) {
    cout << "No solution" << endl;
  } else if (c > 0) {
    int c1 = 1;
    int i = 0;
    for (; i < str.length(); i++) {
      char ch = str[i];
      if (ch == '@' and (i == 0 or i == (str.length() - 1))) {
        break;
      } else if (ch == '@' and (i > 0 and i < (str.length() - 1))) {
        char ch1 = str[i - 1];
        char ch2 = str[i + 1];
        if (ch1 == ',' or ch2 == ',') {
          break;
        }
        if (ch1 != ',' and ch2 != ',' and c1 != c) {
          string str1 = str.substr(0, i + 2);
          string str2 = str.substr(i + 2);
          str = str1 + ',' + str2;
          c1 = c1 + 1;
        }
        if (ch1 != ',' and ch2 != ',' and c1 == c) {
          continue;
        }
      }
    }
    if (i < str.length()) {
      cout << "No solution" << endl;
    }
    if (i >= str.length()) {
      cout << str << endl;
    }
  }
  return 0;
}
