#include <iostream>
#include <cstdio> 
using namespace std;
const int N=1e6+7;
struct node{
    int v,nxt,pre;
}a[N];
void del(int x){
    a[a[x].pre].nxt=a[x].nxt;
    a[a[x].nxt].pre=a[x].pre;
}
int main() {
    freopen("Gold_coin.in","r",stdin);
    freopen("Gold_coin.out","w",stdout);
	int n,k;
    cin>>n>>k;
    int hd=0,tl=n+1;
    a[hd].nxt=1;
    a[tl].pre=n;
    for(int i=1;i<=n;i++){
        a[i].v=i;
        a[i].pre=i-1;
        a[i].nxt=i+1;
    }
    while(n>=2){
        int now=hd;
        int cnt=0;
        while(true) {
            cnt++;
            now=a[now].nxt;
            if(now==tl) break;
            if(cnt%k==1){
                del(now);
//                cout<<a[now].v;
                n--;
                if(n==1) break;
            }
        }
    }
    cout<<a[a[hd].nxt].v;
    return 0;
}