#include <bits/stdc++.h>
using namespace std;
int cond = 1;
int main() {
  char s[213];
  scanf("%s", s);
  string w, ret;
  for (int i = 0; s[i]; i++)
    if (s[i] == '@') {
      if (ret.empty() && w.empty()) {
        puts("No solution");
        return 0;
      }
      if (!ret.empty() && ((int)((w).size())) < 2) {
        puts("No solution");
        return 0;
      }
      if (ret.empty())
        ret = w + "@";
      else
        ret += (string("") + w[0]) + "," + w.substr(1) + "@";
      w = "";
    } else
      w += s[i];
  if (w.empty() || ret.empty()) {
    puts("No solution");
    return 0;
  }
  ret += w;
  puts(ret.c_str());
  return 0;
}
