View Code of Problem 120

#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <math.h>
int main() {
	int h,m,h1,m1,s1,s2,i,j;
	while(scanf("%d:%d",&h,&m)!=EOF){
		int count=0;
		scanf("%d:%d",&h1,&m1);
		s1=h*2500+m;
		s2=h1*2500+m1;
		for(i=s1;i<=s2;i++){
			int k=sqrt(i);
			for(j=2;j<=k;j++){
				if(i%j==0){
					break;
				} 
			}
			if(j>k){
				count++;
			}
		}
		printf("%d\n",count);
}
}