#include <bits/stdc++.h>
using namespace std;
char s[250];
int main() {
  scanf("%s", s);
  int len = strlen(s);
  int t = 1;
  if (s[0] == '@' || s[len - 1] == '@') {
    t = 0;
  }
  int f = 0;
  for (int i = 1; i < len - 1; i++) {
    if (s[i] == '@') {
      if (s[i + 1] == '@' || s[i + 2] == '@') {
        t = 0;
      }
      f++;
    }
  }
  int k = 0;
  if (t == 0 || f == 0)
    printf("No solution\n");
  else {
    for (int i = 0; i < len; i++) {
      if (s[i] == '@' && k < f - 1) {
        printf("%c%c,", s[i], s[i + 1]);
        i++;
        k++;
      } else
        printf("%c", s[i]);
    }
    printf("\n");
  }
  return 0;
}
