C :

#include <stdio.h>
#include <math.h>
#define e 2.718282

double boSong(int i,double x);
int jiCheng(int i);
int main()
{
	int m,n,i;
	double result,x;
	while(scanf("%d %d",&m,&n))
	{
		if(m==0&&n==0)
		break;
		x=m*0.0001;
	
		for(i=0,result=1;i<n;i++)
		  result-=boSong(i,x);
        printf("%.4lf\n",result);
        /* printf("%lf\n %d", boSong(0,x),jiCheng(0));*/
		 
		
	}
}
double boSong(int i,double x)
{
	return pow(x,i)*pow(e,-x);
}
int jiCheng(int i)
{
	
	if(i==0)
	return 1;
	else
	return (i*jiCheng(i-1));
}

C++ :

#include<stdio.h>
#include<math.h>

int main(){
	int m, n;
	while(scanf("%d%d", &m, &n) != EOF){
if(m == 0 && n == 0)
  return 0;
		double a, b;
		a = 1 / exp(0.0001 * m);
		b = a;
		for(int i = 1; i < n; i++){
			a *= (0.0001 * m) / i;
			b += a;
		}
		printf("%.4lf\n", 1 - b);
	}
	return 0;
} 

Python :

# coding=utf-8
e = 2.718282
while True:
    m, n = map(int, input().split())
    if m == 0 and n == 0:
        break
    a = 1 / e ** (0.0001 * m)
    b = a
    for i in range(1, n):
        a = a * (0.0001 * m) / i
        b += a
    print(f"{1 - b:.4f}")