#define _CRT_SECURE_NO_WARNINGS_

#include <iostream>
#include <algorithm>
#include <vector>
#include <cmath>
#include <string>

#define sz(a) int(a.size())
#define all(a) a.begin(), a.end()
#define fore(i, l, r) for(int i = int(l); i < int(r); i++)
#define forn(i, n) fore(i, 0, n)
#define pb push_back
#define x first
#define y second


using namespace std;


int main() {
    ios_base::sync_with_stdio(0);
	cin.tie(0);
	#ifdef _DEBUG
    	freopen("input.txt", "r", stdin);
    	freopen("output.txt", "w", stdout);
    #endif
    string s;
    cin >> s;
    string s1 = "1234567890qwertyuiopasdfghjklzxcvbnmQWERTYUIOPASDFGHJKLZXCVBNM_";
    int j = 0;
    int cnt = 0;
    while (s[j] != '@') {
        if (s1.find(s[j]) != -1) {
            cnt++;
            if (cnt > 16) {
                cout << "NO";
                return 0;
            }
        }
        else {
            cout << "NO";
            return 0;
        }
        j++;
    }
    if (s[sz(s) - 1] == '@') {
        cout << "NO";
        return 0;
    }
    if (cnt == 0) {
        cout << "NO";
        return 0;
    }
    int ind = j + 1;
    cnt = 0;
    bool f = 0;
    int k = 0;
    int cl = 0;
    int toc = 0;
    bool w = 1;
    fore(i,ind,sz(s)) {
        if (s[i] != '.') {
            if (s[i] == '/') {
                f = 1;
                ind = i;
                break;
            }
            else {
                if (s1.find(s[i]) != -1) {
                    cnt++;
                    if (cnt > 16) {
                        cout << "NO";
                        return 0;
                    }
                }
                else {
                    cout << "NO";
                    return 0;
                }
            }
        }
        else {
            w = 0;
            if (s[i] == '.' && s[i + 1] == '.') {
                cout << "NO";
               return 0;
           }
            toc++;
            cl ++;
            k += cnt;
            cnt = 0;
            if (k > 32 || k < 1) {
                cout << "NO";
                return 0;
            }
        }
    }
    if (f == 1) {
        if (s[ind - 1] == '.') {

        }
        else {
            cl++;
        }
    } else {
        if (s[sz(s) - 1] == '.') {

        }
        else {
            cl++;
        }
    }
    if (w == 1 && cnt > 1) {

    }
    else {
        if (toc >= cl) {
            cout << "NO";
            return 0;
        }
    }
    if (cl < 1) {
        cout << "NO";
        return 0;
    }
    if (f == 1) {
        cnt = 0;
        fore(i,ind + 1,sz(s)) {
            if (s1.find(s[i]) != -1) {
                cnt++;
                if (cnt > 16) {
                    cout << "NO";
                    return 0;
                }
            }
            else {
                cout << "NO";
                return 0;
            }
        }
        if (cnt > 1) {
            cout << "YES";
        }
        else cout << "NO";

    } else {
        cout << "YES";
    }
}