#include <bits/stdc++.h>
using namespace std;
int main() {
  string str;
  int a, b, l, cnt, flag;
  while (cin >> str) {
    l = str.length();
    cnt = 0;
    flag = 0;
    for (a = 0; a < l; a++) {
      if (str[a] == '@') cnt++;
    }
    if (str[0] == '@' || str[l - 1] == '@') {
      flag = 1;
    } else if (cnt == 0)
      flag = 1;
    for (a = 0; a < l - 2; a++) {
      if ((str[a] == '@' && str[a + 1] == '@') ||
          (str[a] == '@') && str[a + 2] == '@') {
        flag = 1;
        break;
      }
    }
    if (flag == 1)
      cout << "No solution\n";
    else {
      for (a = 0; a < l; a++) {
        if (str[a] == '@' && cnt > 1) {
          cout << str[a] << str[a + 1] << ",";
          a++;
          cnt--;
        } else
          cout << str[a];
      }
      cout << '\n';
    }
  }
  return 0;
}
