//Extended gcd -> Recursive

tuple<int,int,int> extended_gcd( int a, int b){
	
	if( b == 0 ){
		return {1,0,a};
	}
	
	int x,y,g;
	tie(x,y,g) = extended_gcd( b , a%b );
	return {y , x - (a/b)*y , g};
}