#include <stdio.h>
#include <math.h>
int main() {
    int a, b;
    while (scanf("%d %d", &a, &b) != EOF) { // 注意 while 处理多个 case
        double sum = 0.0;
        double n = a;
        for (int i = 1; i <= b; i++)
        {
            sum += n;
            n = sqrt(n);
        }
        printf("%.02lf\n", sum);
    }
    return 0;
}