#include <stdio.h>
#include <math.h>
#include <string.h>

#define NMAX 100000
int countedges[NMAX];

int main() {
  int N, P, x, y;
  scanf("%d %d", &N, &P);
  memset(countedges,0,sizeof(int)*N);
  int nleaves = 0;
  for(int i = 0; i < N-1; i++) {
    scanf("%d %d", &x, &y);
    countedges[x]++;
    countedges[y]++;
  }
  for (int i = 0; i < N; i++) 
    if (countedges[i] == 1) nleaves++;
  printf("%d\n",2*(P/nleaves)+(P % nleaves >=2? 2 : P % nleaves));
  return 0;
}