View Code of Problem 120

#include<iostream>
#include<vector>
#include<algorithm>
#include<string>
#include<climits>
#include<cmath>
#include<map>
#include<set>

using namespace std;

bool judge(int num) {

	if (num == 1)
		return true;

	for (int i = 2; i <= sqrt(num); i++) {

		if (num % i == 0)
			return false;
	}

	return true;
}

int main()
{
	int begin_h, begin_m, end_h, end_m;

	while (~scanf("%d:%d", &begin_h, &begin_m)) {

		scanf("%d:%d", &end_h, &end_m);

		int begin = begin_h * 60 + begin_m;
		int end = end_h * 60 + end_m;

		int res = 0;
		for (int i = begin; i <= end; i++) {

			int h = i / 60;
			int m = i - (h * 60);

			if (judge(h * 2500 + m))
				res++;
		}

		cout << res << endl;
	}
}