穿越隧道
A. Vasya and Socks
#include <bits/stdc++.h>
using namespace std;
typedef long long ll;
const int N = 1e6 + 10;
int a,b;
int main(){
cin >> a >> b;
int ans = a + a / b;
int u = a / b;
int r = a % b;
while(u != 0){
if(r != 0){
u += r;
}
r = u % b;
u /= b;
ans += u;
}
cout << ans << endl;
return 0;
}