#include <bits/stdc++.h>
using namespace std;
char str[205];
vector<int> v;
int main() {
  while (cin >> str) {
    int i, j;
    int len = strlen(str);
    bool ok = 1;
    v.clear();
    v.push_back(-2);
    bool kk = 0;
    for (i = 0; str[i]; i++) {
      if (str[i] == '@') {
        v.push_back(i);
        kk = 1;
      }
    }
    if (!kk) {
      printf("No solution\n");
      continue;
    }
    for (i = 1; i < v.size(); i++) {
      if (v[i] - v[i - 1] <= 2) {
        ok = 0;
        break;
      }
    }
    int sz = v.size();
    if (v[sz - 1] == len - 1) {
      ok = 0;
    }
    if (!ok) {
      printf("No solution\n");
    } else {
      for (i = 0; i < len;) {
        if (str[i] == '@') {
          if (i != v[sz - 1]) {
            cout << str[i];
            i++;
            cout << str[i] << ",";
            i++;
          } else {
            cout << str[i];
            i++;
          }
        } else {
          cout << str[i];
          i++;
        }
      }
      cout << endl;
    }
  }
  return 0;
}
