Double recursion in function of Ackermann

Question

My teacher asked to make a program using double recursion to generate values of the Ackermann function, in which it is defined for integer and non-negative values m and n as this example:

I made that code but it’s making a mistake and I don’t know where I’m going wrong:

#include <stdlib.h>
#include <stdio.h>

int valor(int m, int n){
    if (m == 0){
        return n + 1;
    } else if((m > 0) && (n == 0)){
        return valor(m - 1, 1);
    } else if((m > 0) && (n > 0)){
        return valor(m - 1, valor(m, n - 1));
    }
}
  

int teste(int n1, int n2){
    int A;
    A = valor(n1, n2);
    return 0;
}

int main() {
    for (int x = 0; x <= 4; ++x) {
        for (int y = 0; y <= 4; ++y) {
            teste(x,y);
        }
    }
    return 0;
}