STOCKTON — For 120 Discovery Challenge Academy cadets, the ability to dream, believe and achieve will keep them on the right path to success.That is what cadet Ignacio Mancha told fellow graduates at the academy’s Class 3 graduation ceremony Saturday at the Bob Hope Theatre in downtown Stockton.Mancha was one of 34 cadets in Class 3 to receive a high school diploma upon completion of the academy’s program this year.