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 <bits/stdc++.h>

#define rep(i, n) for (int i = 0; i < int(n); i++)
#define rrep(i, n) for (int i = int(n) - 1; i >= 0; i--)
#define reps(i, n) for (int i = 1; i <= int(n); i++)
#define rreps(i, n) for (int i = int(n); i >= 1; i--)
#define repc(i, n) for (int i = 0; i <= int(n); i++)
#define rrepc(i, n) for (int i = int(n); i >= 0; i--)
#define repi(i, a, b) for (int i = int(a); i < int(b); i++)
#define repic(i, a, b) for (int i = int(a); i <= int(b); i++)
#define each(x, y) for (auto &x : y)
#define all(a) (a).begin(), (a).end()
#define bit(b) (1ll << (b))

using namespace std;

using i32 = int;
using i64 = long long;
using u64 = unsigned long long;
using f80 = long double;
using vi32 = vector<i32>;
using vi64 = vector<i64>;
using vu64 = vector<u64>;
using vf80 = vector<f80>;
using vstr = vector<string>;

inline void yes() { cout << "Yes" << '\n'; exit(0); }
inline void no() { cout << "No" << '\n'; exit(0); }
inline i64 gcd(i64 a, i64 b) { if (min(a, b) == 0) return max(a, b); if (a % b == 0) return b; return gcd(b, a % b); }
inline i64 lcm(i64 a, i64 b) { return a / gcd(a, b) * b; }
inline u64 xorshift() { static u64 x = 88172645463325252ull; x = x ^ (x << 7); return x = x ^ (x >> 9); }
void solve(); int main() { ios::sync_with_stdio(0); cin.tie(0); cout << fixed << setprecision(16); solve(); return 0; }
template <typename T> class pqasc : public priority_queue<T, vector<T>, greater<T>> {};
template <typename T> class pqdesc : public priority_queue<T, vector<T>, less<T>> {};
template <typename T> inline void amax(T &x, T y) { if (x < y) x = y; }
template <typename T> inline void amin(T &x, T y) { if (x > y) x = y; }
template <typename T> inline T power(T x, i64 n, T e = 1) { T r = e; while (n > 0) { if (n & 1) r *= x; x *= x; n >>= 1; } return r; }
template <typename T> istream& operator>>(istream &is, vector<T> &v) { each(x, v) is >> x; return is; }
template <typename T> ostream& operator<<(ostream &os, vector<T> &v) { rep(i, v.size()) { if (i) os << ' '; os << v[i]; } return os; }
template <typename T, typename S> istream& operator>>(istream &is, pair<T, S> &p) { is >> p.first >> p.second; return is; }
template <typename T, typename S> ostream& operator<<(ostream &os, pair<T, S> &p) { os << p.first << ' ' << p.second; return os; }

void solve() {
  f80 v;
  while (cin >> v) {
    int n = ceil((4.9 * v * v / 9.8 / 9.8 + 5) / 5);
    cout << n << '\n';
  }
}

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

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

C++: #include <iostream>
#include <cstdio>
using namespace std;
int LeastHeight(double v) {
  double y;
  int N;
  y = v * v / 19.6;
  N = int((y + 5) / 5 + 1);
  return N;
}

int main() {
  double v;
  while(cin >> v) {
	cout << LeastHeight(v) << endl;
  }
  //data();
  return 0;
}


/*-- check --*/
void data() {
  double v, y, t;
  int N;

  printf("t\tv\ty\tN\n");
  for(t = 1; t <=10; t += 0.5) {
	v = 9.8 * t;
	y = v * v / 19.6;
	N = int((y + 5) / 5 + 1);
	printf("%.1f\t%.2f\t%.2f\t%d\n", t, v, y, N);
  }
}

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

int main(){
  double v;
  while(~scanf("%lf",&v))
    printf("%d\n",(int)v*v/98+2);
}

C++: #include<bits/stdc++.h>
using namespace std;
int serch(double speed,int floor)
{
    if(speed<9.8*sqrt((5*floor-5)/4.9))return floor;
    return serch(speed,floor+1);
}
int main()
{
    int n;
    double x,y,qux;
    while(cin>>qux){
        n=serch(qux,1);
        cout<<n<<endl;
    }
}

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

int main(){
	double limit;
	double t;
	double y;
	double n;
	while(cin >> limit){
		t = limit / 9.8;
		y = 4.9 * t * t;
		n = (int)((y+5)/5+0.9);
		cout << n << endl;
	}
	return 0;
}

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

using namespace std;

const static double g = 9.8;
int main() {
  // Energy conservation law
  // mgh = (1/2)mv^2
  double v;
  while(cin >> v) {
    double h = (1./2.) * v * v / g;
    int N = 1;
    while(true) {
      if((double)(N*5 - 5) > h) {
        break;
      }
      N++;
    }
    cout << N << endl;
  }
}

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

int main()
{
	double get ;
	double high ;
	int sol ;

	while( cin >> get )
	{
		high = 4.9 *(get/9.8)*(get/9.8) ;

		int tmp = high*100 ;
		if( tmp %5 == 0 )
		{
			sol = high/5 +1 ;
		}
		else
		{
			sol = high/5 +2 ;
		}

		cout << sol << endl ;
	}

	return 0 ;
}

C++: //何階から落とす？
#include<cstdio>
#include<cmath>

using namespace std;

int main(void){
	double in,y,h,t;
	int ans;

	while(scanf("%lf",&in)==1){
		t=in/9.8;
		y=4.9*(t*t);
		h=(y+5)/5;
		ans=ceil(h);
		printf("%d\n",ans);
	}

	return 0;
}

C++: #include <bits/stdc++.h>
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;
    if (kai % 5 == 0) {
      kai++;
    } else {
      kai += 2;
    }
    cout  << kai << endl;
  }
}

C++: #include<stdio.h>


int main(void){
	
	double v;
	
	while(scanf("%lf", &v) != EOF){
		double t = v/9.8;
		double y = 4.9*t*t;
		
		int n = y/5+2;
		if(y <= 9.8)n--;
		if((int)y == y)n--;
		
		printf("%d\n", n);
	}
	
	return 0;
}

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

int main(void) {
    double speed;
    while(cin >> speed) {
        double y = (speed / 2) * (speed / 9.8);
        int n = round((y + 5) / 5.0);
        cout << n << endl;
    }
    return(0);
}

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

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

	double v;
	while(cin >> v){

		double t = v / 9.8;	// 2.59...
		double y = t * t * 4.9; // 

		/*// y = n * 5 - 5
		int n = 0;
		if(int(y + 5) % 5 == 0) n = (y + 5) / 5;
		else n = (y + 5) / 5 + 1;
		*/

		int n = 1;
		while(n * 5 - 5 < y){
			++n;
		}
		cout << n << endl;
	}

	return 0;
}

C++: #include<cstdio>
int main(){
  double v,t,y,i;
  while(scanf("%lf",&v)!=EOF){
    t = v/9.8;
    y = 4.9*t*t;
    for(i=0;i*5<y;i++);
    printf("%.0lf\n",i+1);
  }
  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 ans = y/5+1+0.999999999;
  cout << ans  <<endl;
  }

  return 0;
}

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

int main(){
	double v, y;
	while(cin >> v){
		y = 4.9 * pow(v / 9.8, 2);
		int n = 0;
		for(n;;n++)if(y <= 5*n-5)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 N;
		for(N=1;;N++){
			if(5*N-5>=y) break;
		}
		cout<<N<<endl;
	}
	return 0;
}

C++: #include <math.h>
#include <stdio.h>
#include <iostream>
using namespace std;

int main() {
	int n;
	long double v,y;
	while (cin >> v) {
		y = v * v / 9.8 / 2;
		n = y/5;
		if (n*5 < y)
			n++;
		cout << n + 1 << endl;
	}
	return 0;
}