#include <bits/stdc++.h>
using namespace std;
string a;
string b;
int at = 0;
int cnt = 0;
int addat(int, int);
int addstring(int, int);
int addstring2(int, int);
int main() {
  cin >> a;
  if (a[0] == '@' || a[a.size() - 1] == '@') {
    cout << "No solution";
    return 0;
  }
  int last = 0;
  for (int i = 0; i < a.size(); i++) {
    if (a[i] == '@') {
      at++;
      last = i;
    }
  }
  addstring(0, last);
  if (cnt == at)
    cout << b;
  else
    cout << "No solution";
}
int addat(int ind, int last) {
  b += a[ind];
  return addstring2(ind + 1, last);
}
int addstring(int ind, int lastt) {
  bool go = false;
  if (a[ind] == '@') {
    cnt = -1e2;
  } else {
    for (int i = ind; i < a.size(); i++) {
      if (a[i] != '@')
        b += a[i];
      else {
        go = true;
        cnt++;
        return addat(i, lastt);
      }
    }
    if (go == false) {
      cnt = -1e2;
    }
  }
  return 1;
}
int addstring2(int ind, int last) {
  if (a[ind] == '@') {
    cnt = -1e2;
  } else if (ind - 1 == last) {
    for (int i = ind; i < a.size(); i++) {
      b += a[i];
    }
  } else {
    b += a[ind];
    b += ',';
    addstring(ind + 1, last);
  }
  return 1;
}
