#include <bits/stdc++.h>
using namespace std;
char in[500] = {0};
int i = 0, length = 0;
int store[500] = {0}, pos = 0, cur = 1;
int breakp[500] = {0};
int main() {
  memset(store, -500, 450);
  cin.getline(in, 450);
  length = strlen(in);
  for (i = 0; i < length; i++) {
    if (in[i] == '@') {
      pos++;
      store[pos] = i;
    }
  }
  if (store[pos] == length - 1) {
    goto nosolution;
  }
  if (pos == 0) {
    goto nosolution;
  }
  if (store[1] == 0) {
    goto nosolution;
  }
  for (i = 2; i <= pos; i++) {
    if (store[i] - store[i - 1] < 3) {
      goto nosolution;
    }
  }
  store[pos] = -500;
  pos--;
  for (i = 0; i < length; i++) {
    printf("%c", in[i]);
    if (i == store[cur] + 1) {
      printf(",");
      cur++;
    }
  }
  return 0;
nosolution:
  printf("No solution\n");
  return 0;
  return 0;
}
