Codeforce - vasya and isolated vertices

#include<bits/stdc++.h>
using namespace std;
typedef long long ll;
int main()
{
    ll n,m,mx,mn=0,i=1,j=2,k=0;
    scanf("%I64d %I64d",&n,&m);
    k=n/2;
    if(k>=m)
    {
        mn+=(k-m)*2;
        mn+=n-k*2;
    }
    if(k<m)mn=0;
    j=1,k=0;
    while(j<=n && k<m)
    {
        k=j*(j-1)/2;
        if(k>=m)break;
        j++;
    }
    if(m==1)mx=n-2;
    else mx=n-j;
    if (m==0)mx=n,mn=n;
    printf("%I64d %I64d\n",mn,mx);
    return 0;
}