#include <bits/stdc++.h>
#pragma GCC optimize("O3")
#pragma GCC target("sse4")
using namespace std;
template <typename T>
void etch(T V) {
  for (auto x : V) cout << x << ' ';
  cout << '\n';
}
vector<string> vec_splitter(string s) {
  s += ',';
  vector<string> res;
  while (!s.empty()) {
    res.push_back(s.substr(0, s.find(',')));
    s = s.substr(s.find(',') + 1);
  }
  return res;
}
void debug_out(vector<string> __attribute__((unused)) args,
               __attribute__((unused)) long long int idx,
               __attribute__((unused)) long long int LINE_NUM) {
  cerr << endl;
}
template <typename Head, typename... Tail>
void debug_out(vector<string> args, long long int idx, long long int LINE_NUM,
               Head H, Tail... T) {
  if (idx > 0)
    cerr << ", ";
  else
    cerr << "Line(" << LINE_NUM << ") ";
  stringstream ss;
  ss << H;
  cerr << args[idx] << " = " << ss.str();
  debug_out(args, idx + 1, LINE_NUM, T...);
}
const long long int MOD = 1e9 + 7;
const long long int MOD1 = 998244353;
const long long int N = 2e5 + 5;
const long long int INF = 1000111000111000111LL;
const long double EPS = 1e-12;
const long double PI = 3.141592653589793116;
bool is_char(char ch) { return (ch >= 'a' && ch <= 'z'); }
bool is_num(char ch) { return (ch >= '0' && ch <= '9'); }
int32_t main() {
  std::ios_base::sync_with_stdio(0);
  cin.tie(NULL);
  cout.tie(NULL);
  string s;
  cin >> s;
  long long int n = (long long int)((s).size());
  long long int ans = 0;
  for (long long int ptr = 0; ptr < n;) {
    if (s[ptr] != '@') {
      ptr++;
      continue;
    }
    long long int init = ptr;
    long long int l1 = 0, l2 = 0, l3 = 0;
    long long int j = ptr - 1;
    while (j >= 0 && (is_char(s[j]) or is_num(s[j]) or s[j] == '_')) {
      if (is_char(s[j])) l1++;
      j--;
    }
    ptr++;
    bool flg = 0;
    while (ptr < n && s[ptr] != '.') {
      if (!is_char(s[ptr]) && !is_num(s[ptr])) {
        flg = 1;
        break;
      }
      l3++;
      ptr++;
    }
    if (ptr == n or flg) {
      continue;
    }
    ptr++;
    while (ptr < n && is_char(s[ptr])) {
      l2++;
      ptr++;
    }
    if (l3) ans += (l1 * l2);
  }
  cout << ans;
  return 0;
}
