#include <bits/stdc++.h>
using namespace std;
template <typename Arg1>
void __f(const char* name, Arg1&& arg1) {
  std::cerr << name << " : " << arg1 << endl;
}
template <typename Arg1, typename... Args>
void __f(const char* names, Arg1&& arg1, Args&&... args) {
  const char* comma = strchr(names + 1, ',');
  std::cerr.write(names, comma - names) << " : " << arg1 << " | ";
  __f(comma + 1, args...);
}
long long hell = round(1e18);
signed solve() {
  string s;
  cin >> s;
  long long n = s.length();
  long long f = 0;
  if (n < 3 || s[0] == '@' || s[n - 1] == '@')
    cout << "No solution";
  else if (n == 3) {
    if (s[1] == '@')
      cout << s;
    else
      cout << "No solution";
  } else {
    long long i = 1;
    while (s[i + 2]) {
      if (s[i] == '@' && (s[i + 1] == '@' | s[i + 2] == '@')) {
        cout << "No solution";
        return 0;
      }
      i++;
    }
    i = 0;
    long long k = -1;
    while (s[i]) {
      if (s[i] == '@') k = i;
      i++;
    }
    if (k == -1)
      cout << "No solution";
    else {
      i = 0;
      long long f = 0;
      while (s[i]) {
        if (f == 0) {
          cout << s[i];
          if (s[i] == '@') {
            if (i != k) f = 1;
          }
        } else {
          f = 0;
          cout << s[i] << ",";
        }
        i++;
      }
    }
  }
  return 0;
}
signed main() {
  long long t = 1;
  ios_base::sync_with_stdio(false);
  cin.tie(0);
  cout.tie(0);
  ;
  while (t--) {
    solve();
  }
  return 0;
}
