#include <bits/stdc++.h>
using namespace std;
char a[1000];
char c[1000];
vector<char> v[1000];
int main() {
  ios_base::sync_with_stdio(0);
  cin.tie(0);
  int t = 1, tc;
  long long i, j, k, l, m, n;
  while (~scanf("%s", &a)) {
    long long r = 0;
    j = 0;
    l = strlen(a);
    long long pos = 0, pp = 0;
    if (a[0] == '@' || a[l - 1] == '@') pos = 1;
    for (i = 1; i < l; i++) {
      if (a[i] == '@') pp = 1;
      if (a[i] == '@' && j == i) {
        pos = 1;
        break;
      }
      if (a[i - 1] == '@') {
        if (a[i] == '@') {
          pos = 1;
          break;
        } else {
          long long rr = 0;
          for (k = j; k <= i; k++) v[r].push_back(a[k]);
          r++;
          j = i + 1;
        }
      }
    }
    if (pos == 1 || pp == 0) {
      printf("No solution\n");
    } else {
      for (i = 0; i < r; i++) {
        for (k = 0; k < v[i].size(); k++) printf("%c", v[i][k]);
        if (i + 1 < r) printf(",");
      }
      for (i = j; i < l; i++) {
        printf("%c", a[i]);
      }
      printf("\n");
      for (i = 0; i <= r; i++) v[i].clear();
    }
  }
  return 0;
}
