C :

#include <math.h>
#include "stdio.h"
 
double Y(double x, int n){
    if (n == 0) {
        return 0;
    }
    
    return pow(x + Y(x, n - 1), 0.5);
}
int main() {
    double x;
    int n;
    scanf("%lf,%d", &x, &n);
 
    printf("Result=%.2f\n", Y(x,n));
    return 0;
}