TLE求调，必关

#include<bits/stdc++.h>
#define int long long
using namespace std;
int n,k,ans,cnt;
signed main(){
	cin>>n>>k;
	for(int i=0;i<n;i++){
		ans++;
		if(ans%k==0)ans+=1;
	}
	cout<<ans;
	return 0;
}