#include <iostream>
using namespace std;
int main() {
int h1 = 0, m1 = 0, h2 = 0, m2 = 0;
cin >> h1 >> m1;
cin >> h2 >> m2;
cout << (h2 - h1) * 60 + (m2 - m1) << endl;
return 0;
}