#include <bits/stdc++.h>
using namespace std;
int main() {
  string s;
  cin >> s;
  int p = 0, q = 0, l = s.length();
  if (l < 3) {
    printf("No solution\n");
    return 0;
  };
  vector<int> v;
  for (int i = 0; i < (l); ++i)
    if (s[i] == '@') v.push_back(i);
  int vl = v.size();
  if (!vl) {
    printf("No solution\n");
    return 0;
  };
  if (v[0] == 0) {
    printf("No solution\n");
    return 0;
  };
  if (v[vl - 1] == l - 1) {
    printf("No solution\n");
    return 0;
  };
  for (int i = 0; i < (vl - 1); ++i)
    if (v[i + 1] - v[i] < 3) {
      printf("No solution\n");
      return 0;
    };
  while (p != l) {
    printf("%c", s[p]);
    if (q < vl - 1 && p == v[q] + 1) {
      printf(",");
      q++;
    }
    p++;
  }
  printf("\n");
  return 0;
}
