Go: package main

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

func solve(a, b, c int) int {
	if a == 1 && b >= c && b < 10 {
		return 1
	}
	if a == 1 {
		return 0
	}
	ret := 0
	for i := c; i < 10 && i < b; i++ {
		ret += solve(a-1, b-i, i+1)
	}
	return ret
}

func main() {
	scanner := bufio.NewScanner(os.Stdin)
	scanner.Split(bufio.ScanWords)
	for {
		scanner.Scan()
		a, _ := strconv.Atoi(scanner.Text())
		if a == 0 {
			break
		}
		scanner.Scan()
		b, _ := strconv.Atoi(scanner.Text())
		fmt.Println(solve(a, b, 0))
	}
}

C++: #include <iostream>
#include <iomanip>
#include <sstream>
#include <vector>
#include <string>
#include <set>
#include <unordered_set>
#include <map>
#include <unordered_map>
#include <stack>
#include <queue>
#include <deque>
#include <algorithm>
#include <functional>
#include <iterator>
#include <limits>
#include <numeric>
#include <utility>
#include <type_traits>
#include <cmath>
#include <cassert>
#include <cstdio>

using namespace std;
using namespace placeholders;

using LL = long long;
using ULL = unsigned long long;
using VI = vector< int >;
using VVI = vector< vector< int > >;
using VS = vector< string >;
using ISS = istringstream;
using OSS = ostringstream;
using PII = pair< int, int >;
using VPII = vector< pair< int, int > >;
template < typename T = int > using VT = vector< T >;
template < typename T = int > using VVT = vector< vector< T > >;
template < typename T = int > using LIM = numeric_limits< T >;

template < typename T > inline istream& operator>>( istream &s, vector< T > &v ){ for ( T &t : v ) { s >> t; } return s; }
template < typename T > inline ostream& operator<<( ostream &s, const vector< T > &v ){ for ( int i = 0; i < int( v.size() ); ++i ){ s << ( " " + !i ) << v[i]; } return s; }
template < typename T > inline T fromString( const string &s ) { T res; istringstream iss( s ); iss >> res; return res; }
template < typename T > inline string toString( const T &a ) { ostringstream oss; oss << a; return oss.str(); }

#define NUMBERED( name, number ) NUMBERED2( name, number )
#define NUMBERED2( name, number ) name ## _ ## number
#define REP1( n ) REP2( NUMBERED( REP_COUNTER, __LINE__ ), n )
#define REP2( i, n ) REP3( i, 0, n )
#define REP3( i, m, n ) for ( int i = ( int )( m ); i < ( int )( n ); ++i )
#define GET_REP( a, b, c, F, ... ) F
#define REP( ... ) GET_REP( __VA_ARGS__, REP3, REP2, REP1 )( __VA_ARGS__ )
#define FOR( e, c ) for ( auto &&e : c )
#define ALL( c ) begin( c ), end( c )
#define AALL( a ) ( remove_all_extents< decltype( a ) >::type * )a, ( remove_all_extents< decltype( a ) >::type * )a + sizeof( a ) / sizeof( remove_all_extents< decltype( a ) >::type )
#define DRANGE( c, p ) begin( c ), begin( c ) + ( p ), end( c )

#define SZ( v ) ( (int)( v ).size() )
#define EXIST( c, e ) ( ( c ).find( e ) != ( c ).end() )

template < typename T > inline bool chmin( T &a, const T &b ){ if ( b < a ) { a = b; return true; } return false; }
template < typename T > inline bool chmax( T &a, const T &b ){ if ( a < b ) { a = b; return true; } return false; }

#define PB push_back
#define EM emplace
#define EB emplace_back
#define BI back_inserter

#define MP make_pair
#define fst first
#define snd second

#define DUMP( x ) cerr << #x << " = " << ( x ) << endl

int solve( const int K, const int N, const int S )
{
	if ( K == 0 )
	{
		return ( N == 0 || N == 1 ) && S == 0;
	}

	return solve( K - 1, N - 1, S - K ) + solve( K - 1, N, S );
}

int main()
{
	cin.tie( 0 );
	ios::sync_with_stdio( false );
	cout << setprecision( 12 ) << fixed;

	for ( int N, S; cin >> N >> S, ( N || S ); )
	{
		cout << solve( 9, N, S ) << endl;
	}

	return 0;
}

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

int count;

void func(int n, int s, int tmp, int num)
{
	if(tmp == s && n == 0){
		count++;
		return ;
	}

	for(int i = num; (i+tmp) <= s; i++){
		if(i == tmp){
			break;
		}
		func(n-1, s, i+tmp, num+1);
	}
	
	return ;
}

int main(int argc, char **argv){
	int n, s;
	
	while(1){
		cin >> n >> s;
		
		if(n == 0 && s == 0){
			break;
		}
		count = 0;
		
		for(int i = 0; i < s; i++){
			func(n-1, s, i, 1);
		}
		
		cout << count << endl;
	}
	
	return 0;
}

C++: #include<bits/stdc++.h>
using namespace std;
#define rep(i,n) for(int i=0;i<n;i++)
typedef long long ll;
int main(){
    while(true){
        int n,s,ans=0;
        cin>>n>>s;
        if(n==0) break;
        rep(i,pow(2,10)){
            int x=0,y=0,p=i;
            rep(j,10){
                if(p%2) x++,y+=j;
                p=p/2;
            }
            if(x==n&&y==s) ans++;
        }
        cout<<ans<<endl;
    }
}

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

#define loop(v, f, l) for(int v = (f), v##_ = (l); v < v##_; ++v)

using namespace std;

typedef long long int lint;
static inline int in(){ int x; scanf("%d", &x); return (x); }
static inline lint inl(){ lint x; scanf("%lld", &x); return (x); }

int dp[9][101];

void init();
void make_dp(int sum, int prevused, bool* used, int depth);

void init()
{
	bool used[10] = {false};
	make_dp(0, -1, used, 0);
}

void make_dp(int sum, int prevused, bool* used, int depth)
{
	if( depth == 9 )return;
	
	for(int i = prevused + 1; i < 10; i++)
	{
		if( !used[i] )
		{
			sum += i;
			used[i] = true;
			dp[depth][sum]++;
			make_dp(sum, i, used, depth + 1);
			used[i] = false;
			sum -= i;
		}
	}
}

int main()
{
	int n, s;
	init();

	while(true)
	{
		scanf("%d%d", &n, &s);
		if( n == 0 && s == 0 )break;
		printf("%d\n", dp[n - 1][s]);
	}
	return (0);
}