#include <iostream>
using namespace std;
int a,b,c,d,e,f;
int main () {

    cin>>a>>b>>c>>d;
    if (b>d) {
        f=60-b+d;
    }
    else {
        f=d-b;
    }
    e=c-a;
    cout<<e<<f<<endl;
    return 0;
}