In the eight years since its founding, the Mo Ibrahim Prize for Achievement in African Leadership, which is given to African heads of state who have served their constitutionally mandated terms and then stepped down peacefully, has only been awarded four times due to a dearth of candidates who meet the criteria. Name any of the winners OR any of the countries they led.
Joaquim Chissano, Mozambique; Festus Mogae, Botswana; Pedro Pires, Cabo Verde; Hifikepunye Pohamba, Namibia