UVA 10784

#include <bits/stdc++.h>
using namespace std;
#define ll long long
#define test int t; cin>>t; for(int cs=1;cs<=t;cs++)
int main()
{
    ios_base::sync_with_stdio(0);
    cin.tie(0);
    cout.tie(0);

    ll tt=1,n,ans;
    while(cin>>n && n)
    {

        cout<<"Case "<<tt<<": ";
        tt++;

        ans=ceil((3+sqrt(9+8*n))/2);

        cout<<ans<<endl;

    }

    return 0;
}