Go: package main

import (
        "fmt"
        "math"
)

func main() {
        var v, t, h float64
        for {
                _, err := fmt.Scanf("%f", &v)
                if err != nil {
                        break
                }
                t = v / 9.8
                h = 4.9 * t * t
                n := math.Floor(h/5+1.0) + 1.0
                fmt.Printf("%d\n", int(n))
        }
}

C++: #include <iostream>

using namespace std;

int main() {
	double v;
	while (cin >> v) {
		v *= v;
		int n;
		for (n = 1; 19.6*(5*n-5) < v; n++);
		cout << n << endl;
	}
}

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

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

int main() {
	double v;
	
	while (cin >> v) {
		double t = v / 9.8;
		double y = 4.9 * t * t;
		int kai = (y + 5 - 1e-11) / 5;
		kai++;
		cout << kai << endl;
	}
	return 0;
}

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

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

C++: #include<iostream>

int main()
{
	double V,y;

	while(std::cin>> V)
	{
		y=V*V/19.6;

		for(int i=0;;++i)
		{
			if(5*i-5>=y)
			{
				std::cout << i << '\n';
				break;
			}
		}
	}
}

C++: #include <iostream>
#include <string>
using namespace std;
int main(){
    double x,n;
	while(cin>>x){
	int i=1;
	while(true){
		if(i>=1+x*x/98)
			break;
		i++;
	}
	cout<<i<<endl;
	}
	return 0;
}

C++: #include <stdio.h>
int main(){
	double v,n;
	while(scanf("%lf",&v)!=EOF){
		n = (v*v)/98+1;
		//if(n>(double)((int)n))
		printf("%d\n",(int)n+1);
		//else printf("%d\n",(int)n);
	}
	return 0;
}

C++: #define _USE_MATH_DEFINES
#include <iostream>
#include <sstream>
#include <cmath>
#include <algorithm>
#include <queue>
#include <stack>
#include <limits>

typedef long long ll;
using namespace std;

int main()
{
	double cv;
	while(~scanf("%lf",&cv)){
		//v=9.8t
		//y=4.9t^2

		int lb=1;
		int ub=100000000;
		
		for(int i=0;i<100;i++){
			int md = (lb+ub)/2;
			if(sqrt((5*md-5)/4.9) * 9.8 > cv) ub = md;
			else if(sqrt((5*md-5)/4.9) * 9.8 < cv) lb = md;			
		}

		cout << ub << endl;

	}
}

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

int main() {
	double v, t, y;
	while (cin >> v) {
		for (int i = 1;; i++) {
			y = 5 * i - 5;
			t = sqrt(y / 4.9);
			if (v <= 9.8 * t) {
				cout << i << endl;
				break;
			}
		}
	}
	return 0;
}

C++: #include <iostream>
#include <cstdio>
using namespace std;
int main(){
	double a;
	while(cin >> a){
		double y = a*a/19.6;
		for(int i=1;;i++){
			double h = double(5*i-5);
			if(y<=h){
				cout << i << endl;
				break;
			}
		}
	}
}

C++: #include <iostream>
#include <cmath>
using namespace std;
int main() {
	double v;
	while (cin >> v) {
		double N = (4.9*(v/9.8)*(v/9.8))/5.0+1.0;
		cout << (int)ceil(N) << endl;
	}
	return 0;
}

C++: #include <iostream>
#include <string>
#include <vector>
#include <cmath>
#include <algorithm>
#include <cstdlib>
#include <ctime>
#include <cstdio>
#include <functional>
#include <set>
#include <sstream>
#include <map>

using namespace std;

const double eps=1e-10;

int main()
{
	double v;
	while(cin>>v){
		unsigned long long l=1,r=1e16,h;

		for(int i=0;i<1000;i++){

//			cout<<l<<" "<<r<<endl;

			h=(l+r)/2;
			double vv=2.0*9.8*(5*h-5);

			if(v*v>vv) l=h;
			else if(v*v<vv) r=h;
		}

		if( 2.0*9.8*(5*l-5)-v*v>=eps ) cout<<l<<endl;
		else cout<<r<<endl;

	}

	return 0;
}

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

#define REP(i,n) for(int i=0;i<(int)n;++i)
#define FOR(i,c) for(__typeof((c).begin())i=(c).begin();i!=(c).end();++i)
#define ALL(c) (c).begin(), (c).end()

int main() {
  double v;
  while(cin>>v) {
    double x = v*v/2/9.8;
    cout << ceil(x/5)+1 << endl;
  }
}

C++: #define _USE_MATH_DEFINES
#include<iostream>
#include<iomanip>
#include<algorithm>
#include<cctype>
#include<cmath>
#include<cstdio>
#include<deque>
#include<list>
#include<set>
#include<stack>
#include<string>
#include<sstream>
#include<map>
#include<queue>
#include<vector>
using namespace std;

int main() {
	for (double V; cin >> V;) {
		int N; double T, Y;
		T = V / 9.8;
		Y = 4.9*T*T;
		N = ceil((Y + 5) / 5);
		cout << N << endl;
	}
	return 0;
}

C++: #include "bits/stdc++.h"

#define REP(i,num) for(int i=0;i<(num);++i)
#define ALL(c) c.begin(),c.end()
#define PRINTALL(c) for(auto& x:c){cout<<x<<' ';}cout<<endl;
#define PAIRCOMP(c,comp) [](const pair<ll,ll>& lhs,const pair<ll,ll>& rhs){return lhs.c comp rhs.c;}

using namespace std;
using ll = long long;

constexpr ll atcoder_mod = 1e9+7;

template<typename T=int>
T in(){T x; cin >> x; return (x);}
template<typename T=int,typename C=vector<T>>
C vecin(int N){C x(N);REP(i,N){x[i]=in<T>();}return move(x);}

void vout(){cout << endl;}
template<typename Head,typename... Tail>
void vout(Head&& h,Tail&&... t){cout << ' ' << h;vout(forward<Tail>(t)...);}
void out(){cout << endl;}
template<typename Head,typename... Tail>
void out(Head&& h,Tail&&... t){cout << h;vout(forward<Tail>(t)...);}

int main(){
	cin.tie(0);
	ios::sync_with_stdio(false);

	double v;
	while(cin>>v){
		double t=v/9.8;
		double y = 4.9*t*t;
		
		out(ceil((y+5.0)/5.0));
	}
	
	return 0;
}

C++: 
#include<iostream>
#include<stdio.h>
#include<algorithm>

using namespace std;

int main(){
	double  v;

	while(scanf("%lf",&v) != EOF){

		cout << (int)((4.9/5)*((v*v)/(9.8*9.8)) + 1 + 0.9)<< endl;
	}
		return 0;
}

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

const int INF = 1e+9 * 2;
double eps = 1e-10;

int main() {
	double v;
	while(cin >> v){
		double t = v / 9.8;
		double y = 4.9 * pow(t, 2.0);
		double n = (y + 5) / 5;
		if(n - (int)n < eps)
			cout << (int)n << endl;
		else
			cout << (int)n + 1 << endl;
	}
	return 0;
}

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

int main()
{
	double v;
	while (cin >> v)
	{
		int n = 1;
		v *= v;
		while (v > 19.6 * (n * 5 - 5))
		{
			n++;
		}
		cout << n << endl;
	}
	return 0;
}

C++: #include <stdio.h>
int main(){
	double v;
	while(scanf("%lf",&v)!=EOF){
		double t=v/9.8;
		double h=4.9*t*t;
		int n=(h+4.0)/5.0+1.0;
		printf("%d\n",n);
	}
	return 0;
}

C++: #include <cstdio>
#include <algorithm>
#include <cmath>
#include <climits>
using namespace std;

int main() {
	while(true) {
		double s;
		if(scanf("%lf", &s)<1)break;
		double y = s*s/19.6;
		double k = ceil(y/5+1);
		printf("%d\n", (int)k);
	}
	return 0;
}

C++: #include <iostream>

using namespace std;

int main(int argc, char **argv)
{
	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>
using namespace std;

int main() {
  double input;

  while(cin >> input){
    double y = input * input / 19.6;
    
    long long int x = max( 1, (int) ( ( y + 5 ) / 5 - 2 ) );
    while ( true ) {
      if ( y <= ( x - 1 ) * 5 ) {
	cout << x << endl;
	break;
      }
      x++;
    }
  }

  return 0;

}

C++: #include<iostream>
#include<string>
#include<algorithm>
#include<map>
#include<set>
#include<utility>
#include<vector>
#include<cmath>
#include<cstring>
#include<cstdio>
#define loop(i,a,b) for(int i=a;i<b;i++) 
#define rep(i,a) loop(i,0,a)
#define rp(a) while(a--)
#define pb push_back
#define mp make_pair
#define all(in) in.begin(),in.end()
const double PI=acos(-1);
const double EPS=1e-10;
using namespace std;
typedef long long ll;
typedef vector<int> vi;
int main(){
	double n;
	while(cin>>n){
		double t=n/9.8;
		double y=t*t*4.9+5;
		if((int)y%5)y+=5;
		cout<<(int)(y/5)<<endl;
	}
}