#include<stdio.h>
#include<map>
#include<algorithm>
#include<iostream>
#include <string>
#include <vector>
#include <iomanip>
#include <map>
#include <unordered_map>
#include <set>
#include <numeric>

#define MODULO 1000000007ll

using namespace std;

long long p[102000];long long t;long long ooo = 1;
long long tw[102000];
long long pw[102000];
long long sw[102000];
long long twx;long long pwx,swx;
long long nump[102000];
long long numt[102000];
long long pt[102000];
long long b[102000],c[102000];
void maketwin(){
    p[1]  = 1;
    for (long long i = 2; i <= 100010; ++i) {

//        if(i%10000)
//        cout << endl;
        if(p[i] == 0){
            pw[pwx++] = i;
            for (long long j = i * i; j <= 100010 ; j= j + i) {
                p[j]++;
//                cerr<<j <<' ';
            }
            if(i>2)
            if(p[i-2]==0){
                tw[twx++]= i;
                pt[i] = 1;
//                cout << i <<" ";
                if(i > 4){
                    if(p[i-4]==0){
                        sw[swx++]=i;
//                        cout << i <<" "<<swx;
                    }
                }
            }

        }
    }
//    cout << pwx<<endl;
    for (long long k = 1; k <= 100010; ++k) {
        nump[k] = nump[k-1];
        if(p[k] == 0)nump[k]++;
    }
    for (long long k = 1; k <= 100010; ++k) {
        numt[k] = numt[k-1];
        if(pt[k] == 1)numt[k]++;
    }
    b[0] = 1;c[0] = 1;
    for (long long l = 1; l <= 100010; ++l) {
        b[l] = b[l-1] * 2;
        b[l] %= MODULO;
        c[l] = c[l-1] * 2;
        c[l] %= MODULO;
    }
//    for (long long l = 0; l < 100; ++l) {
//        cout << numt[l] <<" ";
//    }
}
long long h1(long long n , long long m){
    if(m < 2 )return 0ll;
    long long ans = 0ll;
//    cout << pw[0]<<"p" <<n << m;
    for (long long i = 0; pw[i]  < n && i < pwx; ++i) {
        long long t = m - 1;
        t%= MODULO;
        t = t * (n-pw[i]);
        t%= MODULO;
        ans = ans + t;
        ans+=MODULO;
        ans%= MODULO;
//        cout << "."<<ans << endl;
    }
//    cout << ans << endl;
    return ans;
}
long long h2(long long n , long long m){
    if(m <3||n<=5)return 0ll;
//    cout <<"m"<<m << endl;
    long long ans = 0ll;
    for (long long i = 0; tw[i]  < n && i < twx ; ++i) {
//        cout << "x"<<tw[i] <<endl;
        if(m%2==0){
            long long t = ((m - 2)/2) * (m - 1);
            t%= MODULO;
            t *=(n - tw[i] );
            t%= MODULO;
            ans = ans +  t;
            ans%= MODULO;
        }
        else{
            long long t = ((m - 1)/2) * (m - 2);
            t%= MODULO;
            t *=(n - tw[i] );
            t%= MODULO;
            ans = ans +  t;
            ans%= MODULO;
        }
//        ans = ans + c[m] - 3 * b[m] + 1;
        ans+=MODULO;
        ans%= MODULO;
    }
    ans *= 2ll;
    ans%= MODULO;
//    cout << ans << endl;
    return ans;
}

long long h3(long long n , long long m){
    if(m <4|| n <=7)return 0ll;
//    cout <<"m"<<m << endl;
    long long ans = 0ll;

//        cout << "x"<<tw[i] <<endl;
//            cout <<"ty";
            long long t =(m-1) * (m- 2) * (m-3) / 6;
            t%= MODULO;

            t *=(n - 7 );
            t%= MODULO;
            ans = ans +  t;
            ans%= MODULO;

//        ans = ans + c[m] - 3 * b[m] + 1;
        ans+=MODULO;
        ans%= MODULO;

//    ans *= 2ll;
    ans%= MODULO;
//    cout << ans << endl;
    return ans;
}
void solve(long long n , long long m){
    long long sum = 0;
    sum += h1(n,m);
    sum%= MODULO;

    sum +=h2(n,m)+ n+MODULO;

    sum%= MODULO;
    sum +=h3(n,m)+ MODULO;

    sum%= MODULO;
    cout << "Case "<<ooo++<<": "<<sum << endl;
}

int main() {
    std::ios::sync_with_stdio(false);
    string s;
cin >>s;
    if(s.size()<4){
        cout <<"No"<<endl;
    }
    else if(s[0] == 'Y'&& s[1] == 'A'&& s[2] == 'K' && s[3] == 'I'){
        cout <<"Yes"<<endl;
    }else{
        cout <<"No"<<endl;
    }
    return 0;
}

Measured memory_bytes: 256