#include <bits/stdc++.h>
using namespace std;
char str[1000];
int main() {
  int len, i, j, lx = 0, flag = 0, bj = -1;
  int ok = 0;
  scanf("%s", str);
  len = strlen(str);
  for (i = 0; i < len; i++) {
    if (str[i] == '@') {
      bj = i;
      if (flag == 0 && lx == 0) ok = 1;
      if (flag >= 1 && lx < 2) ok = 1;
      flag++;
      lx = 0;
    } else
      lx++;
  }
  if (str[len - 1] == '@') ok = 1;
  if (ok || bj == -1)
    printf("No solution\n");
  else {
    for (i = 0; i < len; i++) {
      printf("%c", str[i]);
      if (str[i] == '@') {
        if (i != bj) {
          printf("%c,", str[i + 1]);
          i++;
        }
      }
    }
  }
  return 0;
}
