#include <bits/stdc++.h>
using namespace std;
const int maxn = 205;
char str[maxn];
int main() {
  while (~scanf("%s", str)) {
    int len = strlen(str);
    int num = 0;
    for (int i = 0; i < len; i++) {
      if (str[i] == '@') {
        num++;
      }
    }
    if (num == 0) {
      puts("No solution");
      continue;
    }
    if (str[0] == '@' || str[len - 1] == '@') {
      puts("No solution");
      continue;
    }
    int flag = 1;
    int init = -1;
    for (int i = 0; i < len; i++) {
      if (str[i] == '@') {
        if (init == -1) {
          init = i;
          continue;
        }
        if (i - init <= 2) {
          flag = 0;
          break;
        }
        init = i;
      }
    }
    int tmp = 0;
    if (!flag) {
      puts("No solution");
      continue;
    } else {
      for (int i = 0; i < len; i++) {
        if (tmp && str[i + 1] == '@') {
          printf(",");
        }
        printf("%c", str[i]);
        if (str[i] == '@') {
          tmp = 1;
        }
      }
    }
    puts("");
  }
  return 0;
}
