UVA - 11677 - Alarm Clock

#include <stdio.h>

int main()
{   int h1,m1,h2,m2;
   while(1){
        scanf("%d %d %d %d",&h1,&m1,&h2,&m2);
        if(h1==0&&m1==0&&h2==0&&m2==0)
            break;
        int sum=0;
        if(m1>m2){
            m2+=60;
            h2--;
        }
        sum=m2-m1;
        if(h1>h2){
            h2+=24;
        }
        sum+=60*(h2-h1);
        printf("%d\n",sum);
    }
    return 0;
}