View Code of Problem 120

//120

#include<stdio.h>
#include<math.h>

int f(int a,int b)
{
	int arr[59000];
	int i,j;
	for(i=0;i<59000;i++)
		arr[i]=1;
	arr[0]=0;
	arr[1]=0;
	for(i=2;i<(int)sqrt(59000);i++)
	{
		if(arr[i]==1)
		{
			arr[i]=1;
			for(j=i*2;j<59000;j++)
			{
				if(j%i==0)
					arr[j]=0;
			}
		}
		
	}
	int sum=0;
	for(i=a;i<=b;i++)
	{
		if(arr[i]==1)
			sum++;
	}
	return sum;
	
	
		
}


int main()
{
	int start_h,start_m;
	int end_h,end_m;
	
	
	while(scanf("%d:%d",&start_h,&start_m)!=EOF)
	{
		scanf("%d:%d",&end_h,&end_m);
		int a=start_h*2500+start_m;
		int b=end_h*2500+end_m;
		int sum=f(a,b);
		printf("%d\n",sum);
	}
	
	
	
	
	return 0;
}