View Code of Problem 120

#include<stdio.h>
#include<string.h>
#define N 57560
int prime[N];
int main()
{
	int i,j;
	
	memset(prime,0,sizeof(prime));	
	
	prime[1]=1;
	prime[0]=1;
	//prime[i]的值为0时表示是素数 
	for(i=2;i*i<=N;i++)
	{
		if(prime[i]==0)
		{
			for(j=i*2;j<=N;j++)
			{
				if(j%i==0)
					prime[j]=1;
			}
		}
	}
	

	
	
	int star_h,star_m;
	int end_h,end_m;
	int count_s,count_e;
	int s;
	while(scanf("%d:%d",&star_h,&star_m))
	{
		
		scanf("%d:%d",&end_h,&end_m);
		count_s=star_h*2500+star_m;
		count_e=end_h*2500+end_m;
		s=0;
		for(i=count_s;i<=count_e;i++)
		{
			if(prime[i]==0)
				s++;
		}
		printf("%d\n",s);	
		
	}
	

	
	return 0;
}