function y=funk(x)
tablica;
n=length(X);
pr=zeros(n,n-1);
for i=1:n-1
    pr(i,1)=(F(i+1)-F(i))/(X(i+1)-X(i));
end
for j=2:n-1
    for i=1:n-j
        pr(i,j)=(pr(i+1,j-1)-pr(i,j-1))/(X(i+j)-X(i));
    end
end

L=F(1);
p=1;
for i=1:n-1
    p=conv(p,[1,-X(i)]);
    L=[0 L]+p*pr(1,i);
end
y=polyval(L,x);