Go: package main

import (
	"bufio"
	"fmt"
	"os"
	"strconv"
	"strings"
)

var (
	sc = bufio.NewScanner(os.Stdin)
)

func main() {
	for sc.Scan() {
		if sc.Text() == "0 0" {
			break
		}
		chunks := strings.Split(sc.Text(), " ")
		n, _ := strconv.Atoi(chunks[0])
		p, _ := strconv.Atoi(chunks[1])
		cnts := make([]int, n, n)
		for i := 0; true; i++ {
			j := i % n
			if p == 0 {
				p, cnts[j] = cnts[j], 0
			} else {
				cnts[j]++
				p--
			}

			if p == 0 {
				noneCnt := 0
				winner := 0
				for j, c := range cnts {
					if c == 0 {
						noneCnt++
					} else {
						winner = j
					}
				}
				if noneCnt == n-1 {
					fmt.Println(winner)
					break
				}
			}
		}
	}
}

C++: #define _CRT_SECURE_NO_WARNINGS
#include "bits/stdc++.h"
using namespace std;
#define rep(i, n) for(int i=0; i<(n); ++i)
#define FOR(i, m, n) for(int i=(m); i<(n); ++i)
#define sz(x) ((int)(x).size())
#define all(x) (x).begin(),(x).end()
#define mp make_pair
#define pb push_back
#define dump(x) cerr << #x << " = " << (x) << endl;
#define qp(f) [](auto i){return f;}
using LL=long long;
using VI=vector<int>;
using VL=vector<LL>;
using VS=vector<string>;
using VVI=vector<vector<int>>;
using PII=pair<int, int>;
const int inf = (int)1e9;
const LL MOD = 1000000007;
const double pi = acos(-1.0);
template<class T>T Sort(T & a) { sort(a.begin(), a.end()); return a; }
template<class T>T ReSort(T& a) { sort(a.rbegin(), a.rend()); return a; }
template<class T>T Reverse(T& a) { reverse(a.begin(), a.end()); return a; }
template<class T>void Unique(T& a) { a.erase(unique(a.begin(), a.end()), a.end()); }
template<class T>auto Max(T a) { return *max_element(a.begin(), a.end()); }
template<class T>auto Min(T a) { return *min_element(a.begin(), a.end()); }
template<class T, class U>int Count(T a, U c) { return count(a.begin(), a.end(), c); }
template<class T, class U>U Sum(T a, U init = 0) { return accumulate(a.begin(), a.end(), init); }
template<class T>T Age(T a, T b) { return (a + b - 1) / b; }
template<class T>T gcd(T n, T m) { return m == 0 ? n : gcd(m, n % m); }
template<class T>T lcm(T n, T m) { return n / gcd(n, m) * m; }
string Snum = "0123456789";

/* INPUT */
struct inputter_Str {
	vector<string> inputbuffer;
	string operator [](int n) { while (inputbuffer.size() <= n) { string s; cin >> s; inputbuffer.push_back(s); }return inputbuffer[n]; }
	operator string() { string s; cin >> s; inputbuffer.push_back(s); return s; }
}in;
struct inputter_Int {
	int operator [](int n) { return stoi(in[n]); }
	operator int() { return stoi(string(in)); }
}ini;
struct inputter_LL {
	LL operator [](int n) { return stoll(in[n]); }
	operator LL() { return stoll(string(in)); }
}inl;
struct inputter_Double {
	double operator [](int n) { return stod(in[n]); }
	operator double() { return stold(string(in)); }
}ind;
VI invi(int n, int m) { VI v(m); for (int i = 0; i < m; ++i)v[i] = ini[n + i]; return v; }
VL invl(int n, int m) { VL v(m); for (int i = 0; i < m; ++i)v[i] = inl[n + i]; return v; }
int Suminvi(int n, int m) { return Sum(invi(n, m), 0); }LL Suminvl(int n, int m) { return Sum(invl(n, m), 0LL); }
int Maxinvi(int n, int m) { return  Max(invi(n, m)); }LL Maxinvl(int n, int m) { return Max(invl(n, m)); }
int Mininvi(int n, int m) { return  Min(invi(n, m)); }LL Mininvl(int n, int m) { return Min(invl(n, m)); }

/* OUTPUT */
struct boolswitch { string t, f; boolswitch(string tr, string fa) :t(tr), f(fa) {} }yes("yes", "no"), Yes("Yes", "No"), YES("YES", "NO"), Yay("Yay!", ":(");
struct divizer { string s; divizer(string s_) :s(s_) {} }spc(" "), nosp("");
struct outputter {
	bool flag = false; boolswitch bs; divizer di;
	outputter(bool f, boolswitch b, divizer d) :flag(f), bs(b), di(d) {}
	template<class T>outputter operator ,(T o) {
		if (flag)cout << di.s; cout << o;
		outputter t(true, bs, di); return t;
	}
	outputter operator ,(double o) {
		if (flag)cout << di.s; printf("%.20f", o);
		outputter t(true, bs, di); return t;
	}
	outputter operator ,(bool o) {
		if (flag)cout << di.s; cout << (o ? bs.t : bs.f);
		outputter t(true, bs, di); return t;
	}
	template<class T> outputter operator ,(vector<T> o) {
		if (flag)cout << di.s;
		for (int i = 0; i < (int)o.size(); ++i)cout << o[i] << (i == (int)o.size() - 1 ? "" : di.s);
		outputter t(true, bs, di); return t;
	}
	template<class T, class U> outputter operator ,(pair<T, U> o) {
		if (flag)cout << di.s;
		cout << "[" << o.first, ", " << o.second << "]";
		outputter t(true, bs, di); return t;
	}
	outputter operator ,(outputter o) { cout << '\n'; return o; }
	outputter operator ,(boolswitch b) { outputter t(flag, b, di); return t; }
	outputter operator ,(divizer d) { outputter t(flag, bs, d); return t; }
}out(false, Yes, spc);

/* ANSWER */
struct Answer {
	int mini = INT_MAX, maxi = INT_MIN, sumi = 0;
	LL minl = LLONG_MAX, maxl = LLONG_MIN, suml = 0LL;
	double mind = DBL_MAX, maxd = DBL_MIN, sumd = 0.;
	int count = 0;
	void operator =(int n) { mini = min(mini, n); maxi = max(maxi, n); sumi += n; count++; }
	void operator =(LL n) { minl = min(minl, n); maxl = max(maxl, n); suml += n; count++; }
	void operator =(double n) { mind = min(mind, n); maxd = max(maxd, n); sumd += n; count++; }
}ans;

int solve(int n, int q) {
	vector<int> s(n);
	int wan = q, pos = 0;

	int ret = -1;
	while (true) {
		if (wan) { 
			s[pos]++; wan--;
			if (!wan) {
				if (s[pos] == q) { ret = pos; break; }
			}
		}
		else {
			wan += s[pos]; s[pos] = 0;
		}
		pos = (pos + 1) % n;
	}
	return ret;
}

int main() {
	int n, q;
	while (cin >> n >> q && (n || q)) {
		out, solve(n, q), out;
	}
}

C++: #include <iostream>
#include <vector>
using namespace std;

int main() {
	int n,p;
	
	while(cin >> n >> p,n){
		int wan = p;
		vector<int> te;
		te.resize(n);
	
		int i=0;
		while(1){
			if(wan == 0){
				wan = te[i];
				te[i] = 0;
			}else{
				if(te[i]==p-1) break;
				te[i]++;
				wan--;
			}
		
			i++;
			i = i%n;
		}
	
		cout << i << endl;
	}
	
	return 0;
}

C++: #include <iostream>
//#include <algorithm>
//#include <vector>
//#include <stack>
//#include <queue>
//#include <map>
//#include <cmath>
//#include <string>
//#include <sstream>
//#include <iomanip>
//#include <complex>
using namespace std;
 
//#define ll long long
//#define vvi vector< vector<int> >
//#define All(X) X.begin(),X.end()
//#define FOR(i,a,b) for(int i=(int)(a);i<(int)(b);i++)
#define REP(i,n) for(int i=0;i<(int)(n);i++)
//#define pb push_back 
//ll gcd(ll a,ll b){return b?gcd(b,a%b):a;}
//ll lcm(ll a,ll b){return a/gcd(a,b)*b;}
 
int main(){
  while(1){
    int n, p;
    cin >> n >> p;
    if(n==0&&p==0) break;
    int kago=p;
    int pc[100]={0};
    int i=0;
    while(1){
      int k=i%(n-1);
      if(pc[k]==p){
	cout << k << endl;
	break;}
      if(kago>0){
	kago--;
	pc[k]++;}
      else{
	kago=pc[k];
	pc[k]=0;}
      i++;}
  }

  return 0;
}

C++: #include <iostream>
#include <vector>
using namespace std;

int main(){
	int mayors[50]{0};
	vector<int> ansvec;

	for(;;){
		int n, p;
		cin >> n >> p;
		if (n == 0) break;

		for (int i = 0; i < n; i++) mayors[i] = 0;
		int bowlp = p;
		int turn = 0;
		for(;;){
			if (bowlp == 1 && mayors[turn] == p - 1) break;
			else if (bowlp == 0){
				bowlp += mayors[turn];
				mayors[turn] = 0;
			}
			else{
				mayors[turn]++;
				bowlp--;
			}

			if (turn == n - 1) turn = 0;
			else turn++;
		}
		ansvec.push_back(turn);
	}

	for (int ans : ansvec){
		cout << ans << "\n";
	}
	return 0;
}

C++: #include <bits/stdc++.h>

using namespace std;

int main()
{
    int n, p;
    while(cin >> n >> p, n|p)
    {
        int counts[n];
        fill(counts, counts+n, 0);
        int cup = p;
        int i;
        for(i=0;; i=(i+1==n) ? 0 : i+1)
        {
            if(cup==0)
            {
                cup = counts[i];
                counts[i] = 0;
            }
            else
            {
                cup--;
                counts[i]++;
                if(counts[i]==p) break;
            }
        }
        cout << i << endl;
    }
}