#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <limits.h>
#include <ctype.h>
#include <math.h>
// Yukicoder №371 ぼく悪いプライムじゃないよ
// https://yukicoder.me/problems/no/371
// ***********************
// for debug
#define DEBUG7

#define NOP do{}while(0)
#ifdef DEBUG
#define TRACE(...) do{printf(__VA_ARGS__);fflush(stdout);}while(0)
#define TRACECR do{printf("\n");fflush(stdout);}while(0)
#else
#define TRACE(...) NOP
#define TRACECR NOP
#endif

#define PRINCR printf("\n")
#define NOCR(strig) do{char *p;p=strchr(strig,'\n');if(p)*p='\0';}while(0)
// The out-of-date function
#define	asctime(...)	asctime_s(...)
#define	ctime(...)		ctime_s(...)
#define	strlen(a)	mystr_len(a)
#define lolong long long

// for stdio
#define INPUT(str) do{char *p;fgets(str,sizeof(str),stdin);p=strchr(str,'\n');if(p)*p='\0';}while(0)
#define REP(a,b) for(int a=0;a<(int)(b);++a)
#define INPBUF (250+2)

// ***********************
// ***********************
// ***********************
// ***********************
// ***********************
// ***********************
// ***********************
// ***********************
// 外部変数
// ***********************
// ***********************
// ***********************
unsigned long long	msp( unsigned long long val ) {
    if ((val&1)==0) return 2;
    for (int i=3;i*i<=val;i+=2)
        if (val%i==0) return (unsigned long long)i;
    return (unsigned long long)0;
}
// ***********************
int main() {
	char	str[INPBUF];
	unsigned long long l, hh, val, idx, sp;

	l = hh = val = 0LL;
	INPUT( str );
	sscanf( str,"%lld %lld", &l, &hh );
	sp = 0;
	idx = 0;
	for(unsigned lolong i = l; i <= hh ; i++) {
		val = msp( i );
    	//printf("%lld = msp( %lld )\n",val , i );
		if( sp <= val ) {
			sp = val;
			idx = i;
		}
	}

	printf("%lld\n", idx );

	return 0;
}