/*数列的定义如下：
数列的第一项为n，以后各项为前一项的平方根，求数列的前m项的和
输入数据有多组，每组占一行，由两个整数n（n<10000）和m(m<1000)组成，n和m的含义如前所述。
Output
对于每组输入数据，输出该数列的和，每个测试实例占一行，要求精度保留2位小数。
 */
#include "stdio.h"
#include "math.h"
int main(){
	int n,m,i;
	double s;
	while (scanf("%d %d",&n,&m)!=EOF) {
		s=0;
		for(i=1;i<=m;i++){
			s+=n;
			n=sqrt(n);
		}
		printf("%.2lf\n",s);
	}
return 0;
}

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ODEgNAoyIDIKNjAgMg==

81 4
2 2
60 2