Problem:
Score: 300 points

Problem Statement

Consider an analog clock whose hour and minute hands are A and B centimeters long, respectively.

An endpoint of the hour hand and an endpoint of the minute hand are fixed at the same point, around which each hand rotates clockwise at constant angular velocity. It takes the hour and minute hands 12 hours and 1 hour to make one full rotation, respectively.

At 0 o'clock, the two hands overlap each other. H hours and M minutes later, what is the distance in centimeters between the unfixed endpoints of the hands?

Constraints

All values in input are integers.

1 \leq A, B \leq 1000

0 \leq H \leq 11

0 \leq M \leq 59

Input

Input is given from Standard Input in the following format:

A B H M

Output

Print the answer without units. Your output will be accepted when its absolute or relative error from the correct value is at most 10^{-9}.

Sample Input 1

3 4 9 0

Sample Output 1

5.00000000000000000000

The two hands will be in the positions shown in the figure below, so the answer is 5 centimeters.

Sample Input 2

3 4 10 40

Sample Output 2

4.56425719433005567605

The two hands will be in the positions shown in the figure below. Note that each hand always rotates at constant angular velocity.

Solution in C++ (GCC 9.2.1) (judge verdict: Accepted)

/*Made by Shivam Solanki*/
#include<bits/stdc++.h>
#pragma GCC optimize ("Ofast")
using namespace std;
#define DEBUG(x) cout << '>' << #x << ':' << x << endl;
#define ll long long int
#define endl '\n'
typedef vector<int> vi;
typedef vector<ll> vll;
typedef vector<vll> vvl;
typedef pair<int,int> pii;
typedef pair<ll,ll> pll;
typedef vector<vi> vvi;
typedef vector<bool> vb;
typedef vector<pii> vp;
typedef vector<pll> vpll;
typedef map<int,int> mii;
typedef map<ll,ll> mll;
typedef set<int> sii;
typedef set<ll> sll;
typedef queue<int> qii;
typedef priority_queue<int> pq;
typedef unordered_map<int,int> umii;
typedef unordered_map<ll,ll> umll;
#define all(x) x.begin(),x.end()
#define rep(i,k,n) for (int i = k; i < n; ++i) 
#define repr(i,k,n) for (int i = n; i>=k; --i)
#define repll(i,k,n) for (ll i = k; i < n; ++i) 
#define pb push_back
#define mp make_pair
#define gcd __gcd
#define F first
#define S second
#define fastio ios_base::sync_with_stdio(false); cin.tie(NULL); cout.tie(NULL);
const int INF = 1e9+5;
const int MOD = 1e9+7;
double pi = 2 * acos(0.0); 

double calcAngle(double h, double m){ 
    if (h == 12) h = 0;  
    if (m == 60) m = 0;  
    double hour_angle = 0.5 * (h * 60 + m);  
    double minute_angle = 6 * m;  
    double angle = abs(hour_angle - minute_angle);  
    angle = min(360 - angle, angle);  
    return angle;  
}  

void solve(){
    int a,b,h,m;
    cin>>a>>b>>h>>m;
    double degrees1=calcAngle((double)h,(double)m);
    double radians1=(degrees1*pi)/180;
    cout<<fixed<<setprecision(15)<<sqrt((a*a)+(b*b)-2*a*b*cos(radians1))<<'\n';    
}

int main(){ 
    // #ifndef ONLINE_JUDGE  
        // freopen("input.txt", "r", stdin); 
        // freopen("output.txt", "w", stdout); 
    // #endif 
    fastio;
    int t=1;
    // cin>>t;
    while(t--)
        solve();
    return 0;
}