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
			fmt.Printf("%d\n", int(x))
	}
}

C++: #include <iostream>
#include <cmath>
using namespace std;
int main() {
	double d;
	while(cin >> d) {
		cout << (int) ceil((4.9 * pow(d / 9.8, 2.0) + 5.0) / 5.0) << endl;
	}
	return 0;
}

C++: // -*- coding: utf-8 -*-
// Last-Updated : <2014/06/19 00:45:07 by samui>

#include <algorithm>
#include <iostream>
#include <cstdio>
#include <string>
#include <vector>
#include <climits>
#define MP(a, b) make_pair(a, b)
#define X first
#define Y second
#define rep(i,n) for(int (i) = 0; (i) < (int)(n); ++(i))
#define rer(i,l,n) for(int (i) = l; (i) <= (int)(n); ++(i))
#define reu(i,l,n) for(int (i) = l; (i) < (int)(n); ++(i))
template<typename T,typename U> inline void amin(T &x,U y){ if(y<x) x = y;}
template<typename T,typename U> inline void amax(T &x,U y){ if(x<y) x = y;}
template<typename TYPE,std::size_t SIZE>
std::size_t len(const TYPE (&array)[SIZE]){return SIZE;}
void abc(float x);
int main(int argc, char *argv[])
{
  float a;
  while(std::cin>>a){
    abc(a);
  }
  return 0;
}
void abc(float x)
{

  float t = x/9.8;
  float y = t*t*4.9;;
  float ans = int((y+5)/5.0);;
  while(ans*5-5<y)
    ++ans;
    std::cout<<ans<<std::endl;
}

C++: #include <string>
#include <vector>
#include <algorithm>
#include <iostream>
#include <cstdio>
#include <cstdlib>
#include <cmath>
#include <queue>
#include <map>
#define INF 100000000
#define rep(i,a) for(int i=0;i<(a);i++)

using namespace std;
typedef long long ll;

double solve(double n){
    return 9.8*sqrt((5*n-5)/4.9);
}

int main(){
    while(true){
        double n;
        if(!(cin>>n))break;
        for(int i=1;i<INF;i++){
//        cout<<solve(i)<<endl;
            if(solve(i)>=n){
                cout<<i<<endl;
                break;
            }
        }
    }
    return 0;
}

C++: //include
//------------------------------------------
#include <vector>
#include <list>
#include <map>
#include <set>
#include <deque>
#include <stack>
#include <bitset>
#include <algorithm>
#include <functional>
#include <numeric>
#include <utility>
#include <sstream>
#include <iostream>
#include <iomanip>
#include <queue>
#include <iterator>
#include <cstdio>
#include <cmath>
#include <cstdlib>
#include <cctype>
#include <string>
#include <cstring>
#include <ctime>

using namespace std;

//conversion
//------------------------------------------
inline int toInt(string s) {int v; istringstream sin(s);sin>>v;return v;}
template<class T> inline string toString(T x) {ostringstream sout;sout<<x;return sout.str();}

//math
//-------------------------------------------
template<class T> inline T sqr(T x) {return x*x;}

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

//container util
//------------------------------------------
#define ALL(a)  (a).begin(),(a).end()
#define RALL(a) (a).rbegin(), (a).rend()
#define PB push_back
#define MP make_pair
#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())

//repetition
//------------------------------------------
#define FOR(i,a,b) for(int i=(a);i<(b);++i)
#define REP(i,n)  FOR(i,0,n)

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

//clear memory
#define CLR(a) memset((a), 0 ,sizeof(a))

//debug
#define dump(x)  cerr << #x << " = " << (x) << endl;
#define debug(x) cerr << #x << " = " << (x) << " (L" << __LINE__ << ")" << " " << __FILE__ << endl;

int gcd(int a, int b){
   int tmp;
   while(a%b==0){
      tmp=a%b;
      a=b;
      b=tmp;
   }
}

int lcm(int a,int b){
   return a*b/gcd(a,b);
}

bool prime_number(int n){
   if(n < 2){
      return false;
   }
   else if(n == 2){
      return true;
   }
   if(n % 2 == 0){
      return false;
   }
   for(int i=3;i<=n/i;i+=2){
      if(n % i == 0) return false;
      return true;
   }
}

int main(){
   double v,t,y;
   int n;
   while(cin>>v){
      t=v/9.8;
      y=4.9*pow(t,2);
      n=(y/5)+1;
      if(!y%5) n++;
      cout << n <<endl;
   }
}

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

int main() {
	double v,y;
	int n;
	while (cin >> v) {
		y = v*v / 19.6;
		n = (y-1) / 5;
		cout << n+2 << endl;
	}
	return 0;
}

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

int main() {
	double v;
	while(cin >> v) {
		double y = v*v / 19.6;
		double N = (y+5.0) / 5.0;
		cout << ceil(N) << endl;
	}
	return 0;
}

C++: #include <iostream>
#include <iomanip>
#include <math.h>
#include <utility>
#include <vector>
#include <cstdlib>
#include <algorithm>
#include <climits>
using namespace std;

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

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

#define FOR(i, a, b) for (int i = (a); i < (b); i++)
#define REP(i, n) for (int i = 0; i < (n); i++)
#define RREP(i, n) for (int i = (n) - 1; i >= 0; i--)
#define sz(obj) ((int)(obj).size())
#define pf push_front
#define pb push_back

int main()
{
  double v, y, floor;

  while (cin >> v){
    int t = 1;
    while (9.8 * t < v) t++;
    y = 4.9 * t * t;
    floor = (y - 5) / 5;
    if (v == 0) floor = 0;
    if (v <= 9) floor = 1;
    printf("%d\n", (int)floor + 1);
  }
}

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

int main(void)
{
    double v, t, y, N;
    
    while(cin >> v)
    {
        t = v / 9.8;
        y = 4.9 * t * t;
        N = (y+5)/5;
        cout << (int)++N << endl;
    }
    return 0;
}

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

using namespace std;

int main() {
  char *line = NULL;
  size_t buffer_size = 0;
  while (getline(&line, &buffer_size, stdin) > 0) {
    double required_velocity;
    scanf("%lf", &required_velocity);
    double required_time = required_velocity / 9.8;
    double required_height = 4.9 * required_time * required_time;
    int required_floor = ceil((required_height + 5.0) / 5.0);
    printf("%d\n", required_floor);
  }

  return 0;
}

C++: //Weight

#include<iostream>
#include<cstdio>
#include<cmath>
using namespace std;

bool g[65];

//?????????????????£??°??????????????°?????°??????
int count_bits(unsigned x){
    int count = 0;
    while(x){
        if(x & 1U) count++;
        x >>= 1;
    }
    return count;
}

//unsinged??????bit??°?????????
int int_bit(void){
    return count_bits(~0U);
}
//??£??°?????????????????§?????????????????????????????¨??????????°??????????????????????????´?????????????
void createArray(unsigned x){
    int n = int_bit();
    for(int i = 0; i < n; i++){
        if((x >> i) & 1U) g[i] = true; 
    }
}

int main(void){

    int i = 9;
    unsigned int x;
    int dp[10][10]; // i?????????????????????????????????weight
    //Dp??§???
    
    while((scanf("%d", &x)) != EOF){
       for(int i = 0; i < 65; i++) g[i] = false;
       createArray(x);
       
       //flag????????£???????????????????°???????????????¨???????????????
       for(int i = 0, j = 0; i < 10; i++) {
           if(g[i]) {
               if(j) printf(" ");
               printf("%d", (int)pow(2.0, (double)i));
               j++;
           }
       }
       putchar('\n');
       
    }
    
    return 0;
}

C++: #include <stdio.h>

int main(void) {
  int n, i, j, k;
  double v;
  while(scanf("%lf", &v) != EOF) {
    v /= 9.8;
    double y = 4.9 * v * v;
    y += 5;
    if((int)(y / 5) == y / 5.0) printf("%d\n", (int)(y / 5));
    else printf("%d\n", (int)(y / 5 + 1));
  }
  return 0;
}