#include <stdio.h>
#include <math.h>
int main() {
int m = 0;
double n = 0.00;
while (~scanf("%lf %d", &n, &m))
{
double sum = 0;
int arr[1000] = {0};
for (int i = 0; i < m; i++)
{
sum = sum + n;
n = pow(n, 0.5);
}
printf("%.2f\n", sum);
}
return 0;
}

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