OJ Board

plzzzz tell me why i getting runtime error...
#include<stdio.h>
int main()
{ int i,j,sum,a,b,n;
scanf("%d",&n);

for(i=1;i<=n;i++)
{
scanf("%d",&a);
scanf("%d",&b);
sum=0;
for(j=a;j<=b;j++)
{

if(j%2!=0)
sum=sum+j;
}
printf("Case %d: %d\n",i,sum);


}

}

Why i getting time limit exceeded??? i use integer,,long,,long long all data types....
#include<stdio.h>
int main()
{
long long a,b,c;
for(;;)
{
scanf("%lld %lld",&a,&b);

if(a<b)
{ c=b-a;
printf("%lld\n",c);
}
if(a>b)
{ c=a-b;
printf("%lld\n",a-b);
}


}
return 0;

}