//uva11677 #include <iostream> using namespace std; int main(){ int a, b, c, d; while((cin >> a >> b >> c >> d)){ if(a == b && b == c && c == d && d == 0) break; else if(a > c || (a == c && b > d)) cout << 1440 - ((60 * a + b) - (60 * c + d)) << endl; else cout << (60 * c + d) - (60 * a + b) << endl; } return 0; }