#include <bits/stdc++.h>
char c[250];
bool f[250];
int main() {
  int i;
  while (scanf("%s", &c) != EOF) {
    bool flag = 0;
    memset(f, 0, sizeof(f));
    for (i = 0; i < strlen(c); i++) {
      if (flag == 0 && c[i] == '@')
        break;
      else if (flag == 0 && c[i] != '@')
        flag = 1;
      else {
        if (c[i] == '@')
          if (i + 1 < strlen(c) && c[i + 1] != '@') {
            i++;
            f[i] = 1;
            flag = 0;
          } else {
            break;
          }
      }
    }
    if (i < strlen(c))
      printf("No solution\n");
    else {
      for (i = strlen(c) - 1; i > 0; i--)
        if (c[i] == '@') {
          f[i + 1] = 0;
          break;
        }
      if (i == 0)
        printf("No solution\n");
      else {
        for (i = 0; i < strlen(c); i++) {
          printf("%c", c[i]);
          if (f[i]) printf(",");
        }
        printf("\n");
      }
    }
  }
  return 0;
}
