#include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include using namespace std; inline int toInt(string s) { int v; istringstream sin(s); sin >> v; return v; } template inline string toString(T x) { ostringstream sout; sout << x; return sout.str(); } template inline T sqr(T x) { return x*x; } typedef vector vi; typedef vector vvi; typedef vector vs; typedef pair pii; typedef long long ll; //repetition //------------------------------------------ #define FOR(i,a,b) for(int i=(a);i<(b);++i) #define rep(i,n) FOR(i,0,n) #define P(p) cout<<(p)< >(a, vector(b, 0)) #define ALL(a) (a).begin(),(a).end() #define RALL(a) (a).rbegin(), (a).rend() #define pb push_back #define mp make_pair #define INF (1100000000) #define SZ(a) int((a).size()) #define EACH(i,c) for(typeof((c).begin()) i=(c).begin(); i!=(c).end(); ++i) #define EXIST(s,e) ((s).find(e)!=(s).end()) #define SORT(c) sort((c).begin(),(c).end()) #define MOD 1000000007LL #define FSP(a) cout << fixed << setprecision(a) int gcd(int x, int y) { if (y == 0) return x; else return gcd(y, x%y); } int lcm(int a, int b) { return a / gcd(a, b) * b; } bool is_prime(int n) { for (int i = 2; i * i <= n; i++) { if (n % i == 0) return false; } return n != 1; } map prime_factor(int n) { map res; for (int i = 2; i * i <= n; i++) { while (n % i == 0) { ++res[i]; n /= i; } } if (n != 1) res[n] = 1; return res; } int extgcd(int a, int b, int& x, int& y) {// int d = a; if (b != 0) { d = extgcd(b, a%b, y, x); y -= (a / b)*x; } else { x = 1; y = 0; } return d; } ll mod_pow(ll x, ll n, ll mod) { if (n == 0) return 1; ll res = mod_pow(x * x % mod, n / 2, mod); if (n & 1) res = res * x % mod; return res; } vector split(const string &str, char delim) { vector res; size_t current = 0, found; while ((found = str.find_first_of(delim, current)) != string::npos) { res.push_back(string(str, current, found - current)); current = found + 1; } res.push_back(string(str, current, str.size() - current)); return res; } bool is_kadomatsu(int a, int b, int c) { if (a == b || a == c || b == c)return false; if (a > b && c > b) return true; if (a < b && c < b)return true; return false; } struct UF { int n; vi d; UF(){} UF(int n):n(n),d(n,-1){} int root(int v) { if (d[v] < 0) return v; return d[v] = root(d[v]); } bool unite(int x, int y) { x = root(x); y = root(y); if (x == y) return false; if (size(x) < size(y)) swap(x, y); d[x] += d[y]; d[y] = x; return true; } int size(int v) { return -d[root(v)]; } }; vector divisor(int n) { if (n == 1) return{}; vi res; for (int i = 1; i*i <= n; i++) { if (n%i == 0) { res.emplace_back(i); if (i != 1 && i != n / i)res.emplace_back(n / i); } } return res; } //------------------------------------------------------------- int ans; int cp, m; bool check(vector &nums) { set check; for (int i = 1; i < (1 << m); i++) { int tmp = 0; for (int j = 0; j < m; j++) { if (((i >> j) & 1) >0) { tmp += nums[j]; } } if (EXIST(check, tmp)) { return false; } else { check.insert(tmp); } } return true; } void dfs(int now, vector &nums) { if (now == m) { if (check(nums)) ans++; } else { if (now == 0) { for (int i = 0; i <= cp; i++) { nums.push_back(i); dfs(1, nums); nums.pop_back(); } }else{ for (int i = nums.back() + 1; i <= cp; i++) { nums.push_back(i); dfs(now + 1, nums); nums.pop_back(); } } } } int main() { int a, b, c, d; cin >> a >> b >> c >> d; P((abs(a - c) + abs(b - d)) / 2.0); return 0; //ifstream ifs("soc-LiveJournal1.txt"); //グラフの読み込み //ofstream output("soc-LiveJournal2.txt"); //int u, v; //string s; //bool is_0_start = false; //int count = 0; //rep(i, 4) getline(ifs, s); //for (; ifs >> u >> v;) { // if (u == 0) is_0_start = true; // if (!is_0_start) { // u--; // v--; // } // count++; // if(count%10000==0)cout << count << endl; // output << u << " " << v << endl; //} }