#include <bits/stdc++.h>
char str[210];
int len;
int main(void) {
  while (scanf("%s", str + 2) != EOF) {
    len = strlen(str + 2);
    int i;
    int flag = 0;
    for (i = 2; i < len + 2; i++)
      if (str[i] == '@') {
        flag = 1;
        break;
      }
    if (flag == 0) {
      printf("No solution\n");
      continue;
    }
    str[0] = '@';
    str[1] = 'a';
    str[len + 2] = 'a';
    str[len + 3] = '@';
    flag = 0;
    int cnt = 0;
    int a, b;
    for (i = 0; i < len + 4; i++) {
      if (cnt == 0 && str[i] == '@') {
        cnt++;
        a = i;
      } else if (cnt == 1 && str[i] == '@') {
        b = i;
        if (b - a - 1 <= 1) {
          flag = 1;
          break;
        }
        a = b;
      }
    }
    int s, e;
    if (flag == 1)
      printf("No solution\n");
    else {
      for (i = 2; i < len + 2; i++)
        if (str[i] == '@') b = i;
      s = 2;
      for (i = 2; i < len + 2; i++) {
        if (str[i] == '@') {
          if (i != b)
            e = i + 1;
          else
            e = len + 1;
          int j;
          for (j = s; j <= e; j++) printf("%c", str[j]);
          if (i != b) printf(",");
          i = e;
          s = e + 1;
        }
      }
      printf("\n");
    }
  }
  return 0;
}
