#include <bits/stdc++.h>
using namespace std;
string s;
int main() {
  cin >> s;
  int pos[222], d = 0;
  for (int i = 0; i < s.size(); i++)
    if (s[i] == '@') pos[++d] = i;
  if (s[0] == '@' || s[s.size() - 1] == '@') {
    printf("No solution");
    return 0;
  }
  if (d == 0) {
    printf("No solution");
    return 0;
  }
  for (int i = 1; i < d; i++) {
    if (pos[i + 1] - pos[i] <= 2) {
      printf("No solution");
      return 0;
    }
  }
  pos[0] = -2;
  for (int i = 0; i < d - 1; i++) {
    for (int j = pos[i] + 2; j <= pos[i + 1] + 1; j++) cout << s[j];
    printf(",");
  }
  for (int j = pos[d - 1] + 2; j < s.size(); j++) printf("%c", s[j]);
  printf("\n");
}
