#import
#import
@interface diff: NSObject
- (long long) abs:(long long) x;
@end
@implementation diff
- (long long) abs:(long long) x {
return x > 0 ? x : -x;
}
@end
int main() {
diff *Different = [diff new];
long long a, b;
while (scanf("%lld%lld", &a, &b) == 2)
printf("%lld\n", [Different abs:(a-b)]);
[Different release];
return 0;
}