Former President of Poland, Chairman of the Board of YES, Alexander Kwasniewski, right, and Grigoriy Surkis, Ukrainian tycoon, and former vice-presidents of UEFA talk at the 16th Yalta European Strategy (YES) annual meeting entitled "Happiness Now. New Approaches for a World in Crisis" at the Mystetsky Arsenal Art Center in Kyiv, Ukraine, Friday, Sept. 13, 2019. More than 400 leaders from politics, business and society representing from 26 countries will discuss major global challenges and their impact on Europe, Ukraine and the world. (AP Photo/Efrem Lukatsky)

Ukrainian President Volodymyr Zelenskiy address the 16th Yalta European Strategy (YES) annual meeting entitled "Happiness Now. New Approaches for a World in Crisis" at the Mystetsky Arsenal Art Center in Kyiv, Ukraine, Friday, Sept. 13, 2019. More than 400 leaders from politics, business and society representing from 26 countries will discuss major global challenges and their impact on Europe, Ukraine and the world. (AP Photo/Efrem Lukatsky)

Finnish President Sauli Niinist address to the 16th Yalta European Strategy (YES) annual meeting entitled "Happiness Now. New Approaches for a World in Crisis" at the Mystetsky Arsenal Art Center in Kyiv, Ukraine, Friday, Sept. 13, 2019. More than 400 leaders from politics, business and society representing from 26 countries will discuss major global challenges and their impact on Europe, Ukraine and the world. (AP Photo/Efrem Lukatsky)

Ukrainian filmmaker Oleg Sentsov, former Russian prisoner, show his prison's badge as he address to the 16th Yalta European Strategy (YES) annual meeting entitled "Happiness Now. New Approaches for a World in Crisis" at the Mystetsky Arsenal Art Center in Kyiv, Ukraine, Friday, Sept. 13, 2019. More than 400 leaders from politics, business and society representing from 26 countries will discuss major global challenges and their impact on Europe, Ukraine and the world. (AP Photo/Efrem Lukatsky)

Estonia's President Kersti Kaljulaid address to the 16th Yalta European Strategy (YES) annual meeting entitled "Happiness Now. New Approaches for a World in Crisis" at the Mystetsky Arsenal Art Center in Kyiv, Ukraine, Friday, Sept. 13, 2019. More than 400 leaders from politics, business and society representing from 26 countries will discuss major global challenges and their impact on Europe, Ukraine and the world. (AP Photo/Efrem Lukatsky)

Ukrainian President Volodymyr Zelenskiy addresses the 16th Yalta European Strategy (YES) annual meeting entitled "Happiness Now. New Approaches for a World in Crisis" at the Mystetsky Arsenal Art Center in Kyiv, Ukraine, Friday, Sept. 13, 2019. More than 400 leaders from politics, business and society representing from 26 countries will discuss major global challenges and their impact on Europe, Ukraine and the world. (AP Photo/Efrem Lukatsky)

Ukrainian President Volodymyr Zelenskiy addresses the 16th Yalta European Strategy (YES) annual meeting entitled "Happiness Now. New Approaches for a World in Crisis" at the Mystetsky Arsenal Art Center in Kyiv, Ukraine, Friday, Sept. 13, 2019. More than 400 leaders from politics, business and society representing from 26 countries will discuss major global challenges and their impact on Europe, Ukraine and the world. (AP Photo/Efrem Lukatsky)

Estonia's President Kersti Kaljulaid address to the 16th Yalta European Strategy (YES) annual meeting entitled "Happiness Now. New Approaches for a World in Crisis" at the Mystetsky Arsenal Art Center in Kyiv, Ukraine, Friday, Sept. 13, 2019. More than 400 leaders from politics, business and society representing from 26 countries will discuss major global challenges and their impact on Europe, Ukraine and the world. (AP Photo/Efrem Lukatsky)

Ukrainian tycoon and philanthropist Viktor Pinchuk addresses the 16th Yalta European Strategy (YES) annual meeting entitled "Happiness Now. New Approaches for a World in Crisis" at the Mystetsky Arsenal Art Center in Kyiv, Ukraine, Friday, Sept. 13, 2019. More than 400 leaders from politics, business and society representing from 26 countries will discuss major global challenges and their impact on Europe, Ukraine and the world. (AP Photo/Efrem Lukatsky)

Sheikh Hamad bin Jassim bin Jabor Al-Thani, former prime minister of Qatar, center, Ukrainian tycoon and philanthropist Viktor Pinchuk, right, and Richard Haass, President of the Council on Foreign Relations talk at the 16th Yalta European Strategy (YES) annual meeting entitled "Happiness Now. New Approaches for a World in Crisis" at the Mystetsky Arsenal Art Center in Kyiv, Ukraine, Friday, Sept. 13, 2019. More than 400 leaders from politics, business and society representing from 26 countries will discuss major global challenges and their impact on Europe, Ukraine and the world. (AP Photo/Efrem Lukatsky)