import sequtils,strutils,math
var
    N = stdin.readline.parseInt
    X = stdin.readline.split.map(parseInt)
    Mx = max(X)
proc harf(i : int):int=
    return i div 2
Mx += Mx mod 2
Mx = Mx div 2
X = X.map(harf)
Mx += sum(X)
echo Mx