#include <bits/stdc++.h>
int main() {
  int i;
  char *take, *ss[500], txt[500];
  gets(txt);
  int y = 0;
  for (i = 0; i < strlen(txt) - 1; i++)
    if ((txt[i] == '@') && (txt[i + 1] == '@')) {
      y = 1;
      break;
    }
  if (y == 1)
    printf("No solution\n");
  else if (txt[0] == '@')
    printf("No solution\n");
  else if (txt[strlen(txt) - 1] == '@')
    printf("No solution\n");
  else {
    int k = 0;
    for (take = strtok(txt, "@"); take != NULL; take = strtok(NULL, "@"), k++)
      ss[k] = take;
    int len, flag = 0;
    if (k == 1)
      printf("No solution\n");
    else {
      for (int i = 1; i < k - 1; i++)
        if (strlen(ss[i]) < 2) {
          printf("No solution\n");
          flag = 1;
          break;
        }
      if (flag == 0) {
        for (i = 0; i < k; i++) {
          if (i == 0)
            printf("%s@", ss[i]);
          else if (i == k - 1)
            printf("%s\n", ss[i]);
          else {
            printf("%c,", ss[i][0]);
            for (int j = 1; j < strlen(ss[i]); j++) printf("%c", ss[i][j]);
            printf("@");
          }
        }
      }
    }
  }
}
