import java.util.Scanner;public class Main {    public static void main(String[] args) {        Scanner scanner = new Scanner(System.in);        int start = scanner.nextInt();        int end = scanner.nextInt();        method(start,end);    }    public static void method(int start, int end) {        int count=0;        //write your code here......        if(start==end){            if(start<=2){                count=0;            }else{                for(int i=2;i<start;i++){                    if(start%i==0){                        count=0;                    }else{                        count=1;                    }                }            }        }else if(start<end){            count=coluate(start,end);        }else{            int temp=start;            start=end;            end=temp;            count=coluate(start,end);        }        System.out.println(start+"到"+end+"之间有"+count+"个大于2的素数");    }    public static int coluate(int start,int end){        int count=0;        int index;        if(start>2){            index=start;        }else{            index=3;        }        while(index<=end){            boolean isPrime=true;            for(int i=2;i<index;i++){                if(index%i==0){                    isPrime=false;                }            }            if(isPrime==true){                count++;            }            index++;        }        return count;    }}