#include<stdio.h>
#include<string.h>
int main(){
    long i,j,k,m,n;
    while(scanf("%ld %ld",&m,&n)!=EOF){
        for(i=0;i<m;i++){
            if(i%n==0)
                m++;
                                               
        }                
        printf("%ld\n",m-1);
    }
    return 0;
}