#include <bits/stdc++.h>
using namespace std;
const int N = 250;
char ch[N];
bool flag[N];
int main() {
  scanf("%s", ch + 1);
  int len = strlen(ch + 1);
  int p = 0, last, s = 0;
  for (int i = 1; i <= len; i++) {
    if (ch[i] == '@') {
      if (p != 1) {
        puts("No solution");
        return 0;
      }
      p = 2;
      s++;
    } else {
      if (!p)
        p = 1;
      else if (p == 2) {
        p = 0;
        flag[i] = true;
        last = i;
      }
    }
  }
  if (p == 2 || !s)
    puts("No solution");
  else
    for (int i = 1; i <= len; i++) {
      printf("%c", ch[i]);
      if (flag[i] && i != len && i != last) printf(",");
    }
}
