Go: package main

import (
	"bufio"
	"os"
	"strconv"
	"fmt"
)

func main() {
	scanner := bufio.NewScanner(os.Stdin)
	for scanner.Scan() {
		a, _ := strconv.ParseFloat(scanner.Text(), 64)
			t := a/9.8
			x := t*t*4.9
			ans := (x+5)/5+1
			fmt.Printf("%d\n", int(ans))
	}
}

C++: #include <cstdio>
#include <cstdlib>
#include <iostream>
#include <string>
#include <cmath>
#include <algorithm>
#include <vector>
#include <queue>
#include <stack>

using namespace std;

int main(){
    double in;
    int ans;
    
    while(scanf("%lf",&in)!=EOF){
        ans=(int)(in*in/98);
        printf("%d\n",ans+1);
    }
    
    return 0;
}

C++: #include <iostream>
#include <cmath>
using namespace std;

typedef long long ll;
#define loop(i,a,b) for(ll i=(a); i<ll(b); i++)
#define rep(i,b) loop(i,0,b)

int f(double V){
    rep(i,100000000){
        double y = 5 * i - 5;
        double t = sqrt(y / 4.9);
        double v = 9.8*t;
        if (v >= V) return i;
    }
    return -1;
}

int main(){
    double v;
    while (cin >> v){
        cout << f(v) << endl;
    }
}

C++: #include <cmath>
#include <cstdio>
#include <iostream>

using namespace std;

int main() {
	float v;
	while (scanf("%f", &v) != EOF) {
		printf ("%d\n", (int)ceil((v * v / 19.6 + 5) / 5.0));
	}
	return 0;
}

C++: //include----------------------------------------------------------------------------------------------------------------------
#include <bits/stdc++.h>

//using namespace--------------------------------------------------------------------------------------------------------------
using namespace std;

//define-----------------------------------------------------------------------------------------------------------------------
#define rep(i, n) for(int i = 0; i < n; i++)
#define FOR(i, s, n) for(int i = s; i < n; i++)
#define per(i, n) for(int i = n; i >= 0; i--)
#define ROF(i, s, n) for(int i = s; i >= n; i--)
#define FORIT(i, A) for (auto i : A)
#define PRINT(x) cout << (x) << endl
#define ALL(a)  (a).begin(),(a).end()
#define RALL(a) (a).rbegin(), (a).rend()
#define PB push_back
#define MP make_pair
#define FOREACH(i, n) for (__typeof((n).begin()) i = (n).begin(); i != (n).end(); ++i)
#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 INF 1 << 25
#define CLR(a) memset((a), 0 ,sizeof(a))
#define dump(x)  cerr << #x << " = " << (x) << endl;
#define debug(x) cerr << #x << " = " << (x) << " (L" << __LINE__ << ")" << " " << __FILE__ << endl;
#define sq(n) (n) * (n)

//typedef----------------------------------------------------------------------------------------------------------------------
typedef vector<int> VI;
typedef vector<VI> VVI;
typedef vector<string> VS;
typedef pair<int, int> PII;
typedef long long LL;
typedef unsigned int uint;
typedef unsigned long long ull;

//const------------------------------------------------------------------------------------------------------------------------
const double EPS = 1e-10;
const double PI = acos( -1.0 );

//global-----------------------------------------------------------------------------------------------------------------------
double a;
double test;

//function---------------------------------------------------------------------------------------------------------------------
void main() {
	while ( scanf( "%lf", &a ) != EOF ) {
		for ( int i = 2;; i++ ) {
			test = ( i * 5 - 5 );
			test /= 4.9;
			test = sqrt( test );
			if ( test * 9.8 >= a ) {
				printf( "%d\n", i );
				break;
			}
		}
	}
}

C++: #include<iostream>
int main()
{
	for (double v_min; std::cin >> v_min;)
	{
		double y_min = v_min * v_min / 19.6;
		int y_ceil = static_cast<int>(ceil(y_min));
		int y = y_ceil + (5 - y_ceil % 5) % 5;
		std::cout << (y + 5) / 5 << std::endl;
	}
	return 0;
}

C++: 
#include <iostream>
#include <string>
#include <stack>
#include <math.h>
#include <algorithm>
#include <cstdlib>
#include <ctime>
#include <vector>

using namespace std;





int main()
{
	double v;
	double h;
	int n;
	while (cin >> v) {
		n = 1;
		h = 4.9*(v / 9.8)*(v / 9.8);
		while (h > 5 * (n - 1)) {
			n++;
		}
		cout << n << endl;
	}


	return 0;
}

C++: #include <iostream>
#include <cmath>
using namespace std;

int main() {
  double v;
  int n;
  while (cin >> v) {
    n = ceil(4.9*(v/9.8)*(v/9.8)/5 + 1);
    cout << n << endl;
  }
  return 0;
}

C++: #include<iostream>
#include<iomanip>
#include<string>
#include<algorithm>
#include<cmath>
using namespace std;
int main(){
    float n,t,y,h;
    while(cin>>n){
        t=n/9.8;
        y=4.9*t*t;
        h=(y+5)/5;
        cout<<fixed<<(int)h+1<<endl;
        
    }
    return 0;
}

C++: #include <iostream>
using namespace std;
 
int main()
{
	double v, t, y;
     while(cin >> v)
	{
		t = v / 9.8;
        y = 4.9*t*t;
         for(int i = 1; i > 0; i++)
		{
            if((5*i-5) > y)
			{
                cout << i << endl;
                break;
            }
        }
    }
     
    return 0;
}

C++: #include <iostream>
int main(){for(double v;std::cin>>v;)std::cout<<(int)(v*v/19.6+9.9999)/5<<"\n";}

C++: #include <iostream>
using namespace std;
int main()
{
    double v,hei;
    int flo;
    while(cin>>v)
    {
      //hei=v*v/2*9.8;
      hei=v*v/19.6;
      //cout<<hei<<endl;
      flo=(hei+5)/5+1;
      cout<<flo<<endl;
    }
}

C++: #include<iostream>
using namespace std;

int main() {
	double v;
	while (cin >> v) {
		double t = v / 9.8;
		double d = 4.9*t*t;
		for (int i = 1;; i++) {
			if (5 * i - 5 >= d) {
				cout << i << endl;
				break;
			}
		}
	}
}

C++: #include <iostream>
#include <queue>
#include <stack>
#include <vector>
#include <stdio.h>
#include <algorithm>
#include <string.h>
#include <string>
using namespace std;

#define rep(i,n) for(int i=0;i<int(n);++i)


double v,y,t;
int n;


int main(){
	
	
	while(cin>>v){
		t = v/9.8;
		y = 4.9*t*t;
		rep(i,1000000){
			if(5*i-5>=y){
				n = i;
				break;
			}
		}
		cout<<n<<endl;
	}
	return 0;
}

C++: #ifndef _GLIBCXX_NO_ASSERT
#include <cassert>
#endif
#include <cctype>
#include <cerrno>
#include <cfloat>
#include <ciso646>
#include <climits>
#include <clocale>
#include <cmath>
#include <csetjmp>
#include <csignal>
#include <cstdarg>
#include <cstddef>
#include <cstdio>
#include <cstdlib>
#include <cstring>
#include <ctime>

#ifdef __GXX_EXPERIMENTAL_CXX0X__
#include <ccomplex>
#include <cfenv>
#include <cinttypes>
#include <cstdbool>
#include <cstdint>
#include <ctgmath>
#include <cwchar>
#include <cwctype>
#endif

#include <algorithm>
#include <bitset>
#include <complex>
#include <deque>
#include <exception>
#include <fstream>
#include <functional>
#include <iomanip>
#include <ios>
#include <iosfwd>
#include <iostream>
#include <istream>
#include <iterator>
#include <limits>
#include <list>
#include <locale>
#include <map>
#include <memory>
#include <new>
#include <numeric>
#include <ostream>
#include <queue>
#include <set>
#include <sstream>
#include <stack>
#include <stdexcept>
#include <streambuf>
#include <string>
#include <typeinfo>
#include <utility>
#include <valarray>
#include <vector>

#ifdef __GXX_EXPERIMENTAL_CXX0X__
#include <array>
#include <atomic>
#include <chrono>
#include <condition_variable>
#include <forward_list>
#include <future>
#include <initializer_list>
#include <mutex>
#include <random>
#include <ratio>
#include <regex>
#include <system_error>
#include <thread>
#include <tuple>
#include <typeindex>
#include <type_traits>
#include <unordered_map>
#include <unordered_set>
#endif

#include <array>

using namespace std;

int main ()
{
	double x;
	while( cin >> x )
	{
		cout <<(int) ( pow ( x  , 2.0 )/(2*9.8) + 5 +5-(1e-19)) / 5 << endl;
	}
}