1. General Institute of Water Resources and Hydropower Planning and Design, Ministry of Water Resources Beijing, Beijing 100120, China
2. Department of Mathematics, Islamia College Peshawar, Peshawar, KPK, Pakistan
3. Department of Mathematics, COMSATS University Islamabad, Attock, Pakistan
4. Department of Mathematics, COMSATS University Islamabad, Lahore, Pakistan
5. School of Electrical and Information Engineering, Zhengzhou University of Light Industry, Zhengzhou, Henan Province 450002, China