#include <bits/stdc++.h>
const long double eps = 1e-9;
using namespace std;
int n;
long double dist(pair<long double, long double> a,
                 pair<long double, long double> b) {
  return sqrt((a.first - b.first) * (a.first - b.first) +
              (a.second - b.second) * (a.second - b.second));
}
int used[10000];
vector<int> g[10000];
bool bfs(int s) {
  used[s] = 1;
  queue<int> q;
  q.push(s);
  while (!q.empty()) {
    int v = q.front();
    q.pop();
    for (int i = 0; i < (int)g[v].size(); i++) {
      int u = g[v][i];
      if (used[u] == -1) {
        used[u] = (used[v] % 2) + 1;
        q.push(u);
      } else {
        if (used[u] == used[v]) return false;
      }
    }
  }
  return true;
}
bool ok(long double mid, vector<pair<long double, long double> > a) {
  for (int i = 0; i < (int)10000; i++) g[i].clear();
  for (int i = 0; i < (int)a.size(); i++)
    for (int j = i + 1; j < a.size(); j++) {
      if (dist(a[i], a[j]) + eps < 2 * mid)
        g[i].push_back(j), g[j].push_back(i);
    }
  for (int i = 0; i < (int)a.size(); i++) used[i] = -1;
  for (int i = 0; i < (int)a.size(); i++) {
    if (used[i] == -1)
      if (!bfs(i)) return false;
  }
  return true;
}
int main() {
  string s;
  cin >> s;
  bool ok = true;
  for (int i = 0; i < (int)s.size(); i++)
    if (s[i] == '@') ok = false;
  if (ok) {
    puts("No solution"), exit(0);
  }
  vector<string> ans;
  while (s.size() > 0) {
    if (s[0] == '@') puts("No solution"), exit(0);
    if (s[s.size() - 1] == '@') puts("No solution"), exit(0);
    int i = 0;
    for (; i < s.size(); i++)
      if (s[i] == '@') break;
    if (i == s.size()) {
      ans[ans.size() - 1] += s, s = "";
      continue;
    }
    i++;
    if (s[i] == '@') puts("No solution"), exit(0);
    string q = s.substr(0, i + 1);
    ans.push_back(q);
    if (q.size() != s.size())
      s = s.substr(i + 1);
    else
      s = "";
  }
  for (int i = 0; i < (int)ans.size(); i++) {
    cout << ans[i];
    if (i != ans.size() - 1) cout << ',';
  }
}
