#include <bits/stdc++.h>
using namespace std;
int main() {
  ios_base::sync_with_stdio(false);
  cin.tie(0);
  int n, l, att = 0, com = 0, f = 0;
  char a[900], b, c;
  cin >> a;
  l = strlen(a);
  for (int i = 0; i < l; i++) {
    if (a[i] == '@') att++;
  }
  for (int i = 0; i < l; i++) {
    if (a[i] == '@' && i != 0 && a[i - 1] != ',' && a[i + 1] != '@' &&
        i + 2 != l && att - 1 > com) {
      if (a[i - 1] != '@' && i + 1 != l) {
        b = a[i + 2];
        for (int j = i + 3; j <= l; j++) {
          c = a[j];
          a[j] = b;
          b = c;
        }
        a[i + 2] = ',';
        com++;
        l++;
        a[l] = '\0';
      }
    }
  }
  l = strlen(a);
  for (int i = 0; i < l; i++) {
    if (a[i] == ',') {
      if (a[i - 1] != '@' && a[i + 1] != '@') f++;
    } else
      f;
  }
  if (att - 1 == f && a[l - 1] != '@' && a[0] != '@')
    cout << a << endl;
  else
    cout << "No solution" << endl;
  return 0;
}
