Problem

Source: Romania 1997

Tags: function, induction, algebra, functional equation, IMO 1981, IMO, romania



function f:N×NN (N=N{0})with these conditon: 1- f(0,x)=x+1 2- f(x+1,0)=f(x,1) 3- f(x+1,y+1)=f(x,f(x+1,y))(romania 1997) find f(3,1997)