#include <bits/stdc++.h>
using namespace std ;

#define pb(n) push_back(n)
#define fi first
#define se second
#define all(r) begin(r),end(r)
#define vmax(ary) *max_element(all(ary))
#define vmin(ary) *min_element(all(ary))
#define debug(x) cout<<#x<<": "<<x<<endl
#define fcout(n) cout<<fixed<<setprecision((n))
#define scout(n) cout<<setw(n)
#define vary(type,name,size,init) vector< type> name(size,init)
#define vvl(v,w,h,init) vector<vector<ll>> v(w,vector<ll>(h,init))
#define mp(a,b) make_pair(a,b)

#define rep(i,n) for(int i = 0; i < (int)(n);++i)
#define REP(i,a,b) for(int i = (a);i < (int)(b);++i)
#define repi(it,array) for(auto it = array.begin(),end = array.end(); it != end;++it)
#define repa(n,array) for(auto &n :(array))

using ll = long long;
using pii = pair<int,int> ;
using pll = pair<ll,ll> ;

constexpr ll inf = ((1<<30)-1)*2+1 ;
const double EPS = 1e-8;
const double INF = 1e12;
typedef complex<double> P;//????´???°????????¢?????????????????¨?§£???
namespace std {
  bool operator < (const P& a, const P& b) {//x????????????
    return real(a) != real(b) ? real(a) < real(b) : imag(a) < imag(b);
  }
  bool sorty(const P& a, const P& b) {//y????????????
    return imag(a) != imag(b) ? imag(a) < imag(b) : real(a) < real(b);
  }
  bool same(const P& a, const P& b) {
    P p = a - b;
    if(abs(real(p)) < EPS && abs(imag(p)) < EPS){
      return true;
    }
    return false;
  }
}
double cross(const P& a, const P& b) {//??????
  return imag(conj(a)*b);
}
double dot(const P& a, const P& b) {//??????
  return real(conj(a)*b);
}

struct L : public vector<P> {//??´???
  L(){};
  L(const P &a, const P &b) {
    push_back(a); push_back(b);
  }
};

typedef vector<P> G;

struct C {//???
  P p; double r;
  C(){};
  C(const P &p, double r) : p(p), r(r) { }
};
int ccw(P a, P b, P c) {//3????????????????????§????????§??????????????????
  b -= a; c -= a;
  if (cross(b, c) > 0)   return +1;       // counter clockwise
  if (cross(b, c) < 0)   return -1;       // clockwise
  if (dot(b, c) < 0)     return +2;       // c--a--b on line
  if (norm(b) < norm(c)) return -2;       // a--b--c on line
  return 0; // a--c--b on line
}
int linejudge(const L &ab,const L &cd){ //2??´???????????¢???
  P a = ab[1] - ab[0],b = cd[1] - cd[0];
  if(abs(cross(a,b)) < EPS){ // Parallel
    return 2;
  }
  else if(abs(dot(a,b)) < EPS){ //Orthogonal
    return 1;
  }
  return 0;
}
// L:line,S:segment,P:point
bool intersectLL(const L &l, const L &m) {
  return abs(cross(l[1]-l[0], m[1]-m[0])) > EPS || // non-parallel
    abs(cross(l[1]-l[0], m[0]-l[0])) < EPS;   // same line
}
bool intersectLS(const L &l, const L &s) {
  return cross(l[1]-l[0], s[0]-l[0])*       // s[0] is left of l
    cross(l[1]-l[0], s[1]-l[0]) < EPS; // s[1] is right of l
}
bool intersectLP(const L &l, const P &p) {
  return abs(cross(l[1]-p, l[0]-p)) < EPS;
}
bool intersectSS(const L &s, const L &t) {
  return ccw(s[0],s[1],t[0])*ccw(s[0],s[1],t[1]) <= 0 &&
    ccw(t[0],t[1],s[0])*ccw(t[0],t[1],s[1]) <= 0;
}
bool intersectSP(const L &s, const P &p) {
  return abs(s[0]-p)+abs(s[1]-p)-abs(s[1]-s[0]) < EPS; // triangle inequality
}
// L & P intersection
P projection(const L &l, const P &p) {
  double t = dot(p-l[0], l[0]-l[1]) / norm(l[0]-l[1]);
  return l[0] + t*(l[0]-l[1]);
}
// L????????????P???????°????
P reflection(const L &l, const P &p) {
  return p + 2.0 * (projection(l, p) - p);
}
double distanceLP(const L &l, const P &p) {
  return abs(p - projection(l, p));
}
double distanceLL(const L &l, const L &m) {
  return intersectLL(l, m) ? 0 : distanceLP(l, m[0]);
}
double distanceLS(const L &l, const L &s) {
  if (intersectLS(l, s)) return 0;
  return min(distanceLP(l, s[0]), distanceLP(l, s[1]));
}
double distanceSP(const L &s, const P &p) {
  const P r = projection(s, p);
  if (intersectSP(s, r)) return abs(r - p);
  return min(abs(s[0] - p), abs(s[1] - p));
}
double distanceSS(const L &s, const L &t) {
  if (intersectSS(s, t)) return 0;
  return min(min(distanceSP(s, t[0]), distanceSP(s, t[1])), min(distanceSP(t, s[0]), distanceSP(t, s[1])));
}
double distancePP(const P &p,const P &q){
  return abs(p - q) ;
}
P crosspoint(const L &l, const L &m) {
  double A = cross(l[1] - l[0], m[1] - m[0]);
  double B = cross(l[1] - l[0], l[1] - m[0]);
  if (abs(A) < EPS && abs(B) < EPS) return m[0]; // same line
  if (abs(A) < EPS) assert(false); // !!!PRECONDITION NOT SATISFIED!!!
  return m[0] + B / A * (m[1] - m[0]);
}
P verticalvector(const P &a,const P &b){//2???????????????????????????????????????
  if(a.real() == b.real()){
    return {1.0,0};
  }
  if(a.imag() == b.imag()){
    return {0,1.0};
  }
  P p = a - b;
  P res = {-p.imag(),p.real()};
  return res / abs(p);
}
pair<P,P> crosspointCircle(const C &a,const C &b){
  P m = (a.p+b.p)/2.0;
  P vv = verticalvector(a.p,b.p);
  double u = sqrt( a.r * a.r - norm(a.p - b.p) / 4.0);
  P A = m + u * vv,B = m - u * vv;
  return mp(A,B);
}
// a < b : -1, a > b : 1, a == b : 0
inline int sgn(double a, double b = 0) { return a < b - EPS ? -1 : a > b + EPS ? 1 : 0; }
int circle_judge(const C &a,const C &b){ // return tangent count
  double d = distancePP(a.p,b.p);
  double e = a.r,f = b.r;
  if(sgn(d,e+f) == 1) return 4;
  if(sgn(d,e+f) == 0) return 3;
  if(sgn(d,abs(e-f)) == -1) return 0;
  if(sgn(d,abs(e-f)) == 0 ) return 1;
  return 2;
}

int main(){
  cin.tie(0);
  ios::sync_with_stdio(false);
  double x,y,r;
  cin >> x >> y >> r;
  C c1(P(x,y),r); 
  cin >> x >> y >> r;
  C c2(P(x,y),r); 
  std::cout << circle_judge(c1,c2) << std::endl;
  return 0;
}

Measured memory_bytes: 3292