#include<bits/stdc++.h> using namespace std; int main(){ int v,d,t=0,n,s=0,c=1; cin>>v>>d; //ceil()向上取整 ，盐水有n滴 n=ceil(1.0*v/d); /*if(v%d==0){ n=v/d; }else{ n=v/d+1; }*/ while(s<n){ s=s+c; c++; t++; } t--; t=t+n; cout<<t; return 0; }