Calculati suma:
1 + 2 + 3 + ... + 2014 + 2015.
S = 1 + 2 + 3 + ... + 2014 + 2015
S = 2015 + 2014 + 2013+ ... + 2 + 1
2S = 2016 + 2016+ ...+ 2016
2S = 2016 *2015
S = 2,031,120