Codeforces Panoramix's Prediction

// Accepted
#include <iostream>
#include <cstdio>
#include <cstring>
#include <string>
#include <cmath>
#include <vector>
#define N 100
#define sf scanf
#define pf printf
using namespace std;

int stats[(N/2)+1],arr[N],len=1;

void prime ()
{
    int i,j,qrt;

    for (i=2;i<=N>>1;i++)
    {
        stats[i] = 0;
    }

    qrt = int (sqrt(double (N)));

    for (i=3;i<=qrt;i+=2)
    {
        if (stats[i>>1] == 0) {

        for (j=i*i;j<=N;j+=i+i)
        {
            stats[j>>1] = 1;
        }

        }
    }

    arr[0] = 2;

    for (i=3;i<=N;i+=2)
    {
        if (stats[i>>1] == 0)
        {
            arr[len] = i;
            len++;
        }
    }
}

int main()
{
    prime();

    /*for (int i=0;i<len;i++)
    {
        printf("%d ",arr[i]);
    }*/

    int n,m,d;
    bool f = false;

    cin >> n >> m;

    for (int i=0;i<len;i++)
    {
        if (m == arr[i])
        {
            d = i;

            if (arr[d-1] == n)
            {
                f = true;
                break;
            }
        }
    }

    if (f)
    {
        printf("YES");
    }

    else
    {
        printf("NO");
    }

    return 0;
}