Fish number 1 (F1), the smallest of the seven Fish numbers, is a number defined by Japanese googologist Fish in 2002. It uses modified Ackermann function, defined as the following: * \(S_1(0,y) = y+1\) * \(S_1(x,0) = S_1(x - 1,1)\) * \(S_1(x,y) = S_1(x - 1,S_1(x,y - 1))\) After that, we define the \(S_2\) function that uses \(S_1\) as the base function and in general, we have an \(S_n\) function that uses \(S_{n-1}\) as the base: * \(S_1(0,y) = y+1\) * \(S_z(0,y) = S_{z-1}(y,y)\) for \(z > 1\) * \(S_z(x,0) = S_z(x - 1,1)\) * \(S_z(x,y) = S_z(x - 1,S_z(x,y - 1))\)