Algorithm

A. Panoramix's Prediction
time limit per test
2 seconds
memory limit per test
256 megabytes
input
standard input
output
standard output

A prime number is a number which has exactly two distinct divisors: one and itself. For example, numbers 273 are prime, and 164 are not.

The next prime number after x is the smallest prime number greater than x. For example, the next prime number after 2 is 3, and the next prime number after 3 is 5. Note that there is exactly one next prime number after each number. So 5 is not the next prime number for 2.

One cold April morning Panoramix predicted that soon Kakofonix will break free from his straitjacket, and this will be a black day for the residents of the Gallic countryside.

Panoramix's prophecy tells that if some day Asterix and Obelix beat exactly x Roman soldiers, where x is a prime number, and next day they beat exactly y Roman soldiers, where y is the next prime number after x, then it's time to wait for Armageddon, for nothing can shut Kakofonix up while he sings his infernal song.

Yesterday the Gauls beat n Roman soldiers and it turned out that the number n was prime! Today their victims were a troop of m Romans (m > n). Determine whether the Gauls should wait for the black day after today's victory of Asterix and Obelix?

Input

The first and only input line contains two positive integers — n and m (2 ≤ n < m ≤ 50). It is guaranteed that n is prime.

Pretests contain all the cases with restrictions 2 ≤ n < m ≤ 4.

Output

Print YES, if m is the next prime number after n, or NO otherwise.

Examples
input
Copy
`3 5`
output
Copy
`YES`
input
Copy
`7 11`
output
Copy
`YES`
input
Copy
`7 9`
output
Copy
`NO`

Code Examples

#1 Code Example with C++ Programming

```Code - C++ Programming```

``````#include<bits/stdc++.h>
using namespace std;

#define ll long long
#define endl '\n'
#define debug(n) cout<<(n)<<endl;
const ll INF = 2e18 + 99;

bool prime_check(int m){

if(m % 2 == 0){
return false;
}
bool check = true;
for(int i = 2; i*i <= m; i++){
if(m % i == 0){
check = false;
break;
}
}
return check;
}

int main(){
ios_base::sync_with_stdio(false);
cin.tie(NULL);

int n, m;
cin>>n>>m;

int real_m;
for(int i = n+1; i <= m; i++){
if(prime_check(i)){
real_m = i;
break;
}
}

(real_m == m) ? cout<<"YES"<<endl : cout<<"NO"<<endl;

}``````
Copy The Code &

Input

cmd
3 5

Output

cmd
YES

Demonstration

Codeforcess Solution 80-A A. Panoramix's Prediction ,C++, Java, Js and Python ,80-A,Codeforcess Solution