#include <bits/stdc++.h>
using namespace std;
string buf, res;
char s[300];
int wait = 0, ilast;
int main() {
  gets(s);
  for (int i = 0; s[i]; i++) {
    if (wait == 0) {
      if (isalpha(s[i]))
        wait = 1;
      else {
        printf("No solution");
        return 0;
      }
      buf.push_back(s[i]);
    } else if (wait == 1) {
      if (isalpha(s[i]))
        wait = 1;
      else if (s[i] == '@')
        wait = 2;
      buf.push_back(s[i]);
    } else if (wait == 2) {
      if (isalpha(s[i]))
        wait = 0;
      else {
        printf("No solution");
        return 0;
      }
      buf.push_back(s[i]);
      buf.push_back(',');
      res += buf;
      buf = "";
      ilast = i;
    }
  }
  if (wait == 1 && ilast == 0 || wait == 2) {
    printf("No solution");
    return 0;
  } else if (wait == 1 || wait == 0) {
    res.resize(res.size() - 1);
    res += s + ilast + 1;
  }
  cout << res;
  return 0;
}
