#include <bits/stdc++.h>
int a[1000];
char s[1000];
int find() {
  int k = 0;
  for (int i = 0; s[i]; i++)
    if (s[i] == '@') a[k++] = i;
  return k;
}
int main() {
  int i, j;
  scanf("%s", s);
  int m = find();
  if (a[0] == 0) {
    printf("No solution\n");
    return 0;
  }
  for (i = 0; i < m - 1; i++)
    if (a[i + 1] - a[i] <= 2) {
      printf("No solution\n");
      return 0;
    }
  if (a[m - 1] == strlen(s) - 1) {
    printf("No solution\n");
    return 0;
  }
  if (m == 1) {
    printf("%s\n", s);
    return 0;
  }
  for (i = 0; i <= a[0] + 1; i++) printf("%c", s[i]);
  if (m > 1) printf(",");
  for (i = 0; i < m - 2 && s[a[i]]; i++) {
    j = a[i] + 2;
    for (; j <= a[i + 1] + 1; j++) printf("%c", s[j]);
    if (i != m - 2) printf(",");
  }
  for (j = a[i] + 2; s[j]; j++) printf("%c", s[j]);
  printf("\n");
  return 0;
}
