Riding Bicycle

#include <stdio.h>

int main(){
    int tc, v, d, a, b;
    scanf("%d", &tc);
    for(int i=1;i<=tc;i++){
        scanf("%d %d %d:%d", &v, &d, &a, &b);
        b+=a*60;
        b= ( b - ((double) d/v)*60 < 0 ? (b+1440) - ((double) d/v)*60 : b - ((double) d/v)*60);
        printf("Case #%d: %.02d:%.02d\n", i, b/60, b%60);
    }
    return 0;
}