#include<stdio.h>
int main()
{
    double x,n,i,pro=1,fact=1,sum=1;
    scanf("%lf %lf",&x,&n);
    for(i=1;i<=n;i++)
    {
        pro*=x;
        fact*=i;
        sum+=(pro/fact);
    }
    printf("%.2lf",sum);
    return 0;
}