gears

#include <fstream>
#define Nmax 101
using namespace std;
ifstream f("gears.in");
ofstream g("gears.out");
int n,a[Nmax][Nmax],v[Nmax],x,d[Nmax];

void df(int x,int directie)
{
	v[x]=1;
	d[x]=directie;
	for(int i=1;i<=n;++i)
		if(v[i]==0&&a[x][i]==1)
			df(i,1-directie);
}

int main()
{
    int m,i,j;
    f>>n>>x;
    m=n-1;
    while(m--)
		f>>i>>j,a[i][j]=a[j][i]=1;
	df(x,0);
	for(int i=1;i<=n;++i)
		g<<(d[i]?"S":"D");
	return 0;
}