#include <stdio.h>
#include <string.h>
#include <stdbool.h>
#define maxSize 10000000
bool isPrime[maxSize];
int prime[maxSize];
int main(void)
{
int i, j, num;
memset(isPrime, true, sizeof(isPrime));
isPrime[0] = isPrime[1] = false;
for( i = 0, num = 0 ;i < maxSize ;++i )
{
if(isPrime[i] == false)
continue;
prime[num++] = i;
for( j = 2*i ;j < maxSize ;j+=i )
isPrime[j] = false;
}
int d;
for( d= 1; d < 1000000 ;++d )
{
for( i = 0; i<num-10 ; ++i )
{
for( j = 0;j < 10 ;++j )
{
if(isPrime[ prime[i]+d*j ]==false)
break;
}
if(j==10)
{
printf("%d", d);
return 0;
}
}
}
}
