I m 21 yrs old female . My bmi is 19.8. I have some extra fat on my stomach, thighs and arms.

Being a med student I don't have the time to join a gym. However I do run on treadmill for 30 minutes , thrice a week.

Does anyone know excercises that would be of help for attaining a flat stomach , toned thighs and arms ?

Any advice would be appreciated.