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 <cstring>
#include <climits>
#include <cmath>
#include <ctime>
#include <iostream>
#include <algorithm>
#include <string>
#include <vector>
#include <set>
#include <map>
#include <queue>
#include <deque>
using namespace std;
typedef vector<int> vi;
typedef vector<vi> vvi;
typedef vector<double> vd;
typedef vector<vd> vvd;
typedef pair<int,int> pii;
typedef map<int,int> mii;
#define PI acos(-1.)
#define SQR(x) ((x)*(x))
#define INF (INT_MAX/100)
#define mid(x,y) (x+y)/2
#define ll long long
#define sz(v) ((int)(v).size())
#define rep(i, n) for (int i=0; i<(n); ++i)
#define repf(i, a, b) for (int i=(a); i<=(b); ++i)
#define repd(i, a, b) for (int i=(a); i>=(b); --i)
#define fill(a, b) memset(a, b, sizeof(a))
#define clr(q) while (!q.empty()) q.pop();
#define pb push_back
#define pf push_front
#define itr iterator
#define eps 1e-9

int sgn(double d){
    return d<-eps?-1:d>eps;
}

int main(){
    double v;
    while (~scanf("%lf", &v)){
        cout<<ceil(v*v/2/9.8/5+1)<<endl;
    }
    return 0;
}

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

int main(void)
{
	double v, times, hight, street;

	while (cin >> v) {
		times = v / 9.8;
		hight = 4.9 * times * times;
		street = (hight + 5.0) / 5.0;
		printf("%.0f\n", street);
	}
	
	return 0;
}

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

int main(){
	double v;
	while(cin>>v){
		double y = v*v/19.6;
		for(int i=1; ; i++){
			if(5*(i-1) > y){
				cout << i << endl;
				break;
			}
		}
	}
    return 0;
}

C++: #include<iostream>
#include<cmath>
using namespace std;
int main(){
	double x;
	while(cin >>x){
		for(int i=1;;i++){
			double hight=5*i-5,v=sqrt(4*4.9*hight);
			if(v>=x){cout <<i<<endl;break;}
		}
	}
	return 0;
}

C++: #include<iostream>
#include<algorithm>
#include<string>
#include<cmath>
using namespace std;
int main(){
  int N=1,b=0,t,j;
  double a,v,y,i;
  while(cin >> a){
    N=1;
    b=0;
    i=a/9.8;
    y=4.9*i*i;
    while(b<y){
      b=5*N-5;
      N++;
    }
    N--;
    cout << N << endl;
  }
}

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

int main(){
	double v;

	while ( cin >> v ){
		double y = ( v * v ) / ( 2.0 * 9.8 );
		int f = y / 5 + ( y / 5 - static_cast< int >( y / 5 ) == 0.0 ? 0 : 1 ) + 1;

		cout << f << endl;
	}
	return 0;
}

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

C++: #include <cmath>
#include <iostream>
#include <string>
#include <cstdlib>
#include <cstdio>
#include <algorithm>
#include <sstream>
#include <vector>
#define P(a) ((a)*(a))
using namespace std;

int main(){
    double t,y,v;
    int f;
    while(cin >> v){
        t=v/9.8;
        y=4.9*t*t;
        f=ceil((y+5.0)/5.0);
        cout << f << endl;
    }
    return 0;
}

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

int main(){
	double v;
	while(cin>>v){
		double t=v/9.8;
		double y=4.9*t*t;
	//	int n=(((y+5)/5)*10+5)/10;
		int c=1;
	for(int i=0;0<y;i++){
			y-=5;
			c++;
		}
		cout<<c<<endl;
	//	cout<<n<<endl;
	}
}

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

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 pair<long, long> PLL;
typedef long long LL;
//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(long i=(a);i<(b);++i)
#define REP(i,n)  FOR(i,0,n)

//constant
//--------------------------------------------

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

const long double EPS = 1e-12;
const LL INF = 1e18;


int main(){
	double v;
	while(cin>>v){
		if(v<=0.0+EPS){
			cout<<1<<endl;
			continue;
		}
		double t=v/9.8;
		double y=4.9*t*t;
		int N=(int)ceil(y)/5+1+(((int)ceil(y)%5!=0)?1:0);
		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;
        double n = 1;
        while (5 * n - 5 < y) {
            ++n;
        }
        cout << n << endl;
	}
	return 0;
}

C++: #include <algorithm>
#include <cassert>
#include <cctype>
#include <climits>
#include <cmath>
#include <cstdio>
#include <cstdlib>
#include <cstring>
#include <fstream>
#include <iostream>
#include <iomanip>
#include <iterator>
#include <list>
#include <map>
#include <numeric>
#include <queue>
#include <set>
#include <sstream>
#include <stack>
#include <string>
#include <utility>
#include <vector>
using namespace std;

int main()
{
    double n;
    while(scanf("%lf",&n)!=EOF)
    {
        double y=(n*n)/19.6;
        double k=0.0;
        int i;
        for(i=1;k<y;i++)
        {
            k=5.0*i-5.0;
        }
        printf("%d\n",i-1);
    }
}

C++: #include <iostream>
#include <cmath>
using namespace std;
int main(void){
    double v, y;
    while(cin >> v){
        y=(4.9*v*v)/(9.8*9.8*5)+1;
        cout << ceil(y) << endl;
    }
    return 0;
}

C++: #include<iostream>
using namespace std;
int main(){
  double v,y,t;
  int n,h[100];
  for(int i=0; i<100; i++)
    h[i] = i*5-5;
  while(cin >> v){
    t = v/9.8;
    y = 4.9 * t * t;
    for(int i=0; i<100; i++){
      if(h[i] >= y){
	cout << i << endl;
	break;
      }
    }
  }
}

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

using namespace std;

int main(void) {
	double s;

	while(!cin.eof()) {
		cin >> s;
		if(!cin.eof()) { cout << ceil(((s/9.8)*(s/9.8)*4.9+5)/5) << endl; }
	}

	return 0;
}

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

int main() {
	double v;
	double t, y;
	int n;
	
	while( cin >> v ){
		t = v / 9.8;
		y = 4.9 * t * t;
		n = (y + 4.99999999) / 5 + 1;
		cout << n << endl;
	}
	return 0;
}

C++: #include<iostream>
#include<cstdio>
#include<cmath>
using namespace std;
int main()
{
    double v;
    while(~scanf("%lf",&v)){
        double t=v/9.8;
        double f=4.9*t*t;
        int N=(f+5.0)/5.0+0.5;
        printf("%d\n",N);
    }
    return 0;
}

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

using namespace std;

int main() {
  double v;
  while (cin >> v) {
    double t = v / 9.8;
    double h = 4.9 * t * t;
    double n = (h+5)/5;
    int ans = ceil(n);
    cout << ans << endl;

  }
  return 0;
}

C++: #include <iostream>

using namespace std;

int main()
{
  double v0;
  while (scanf("%lf ", &v0) == 1) {
    cout << (int)((v0 * v0)/ (5.0 * 4.0 * 4.9)) + 1 << endl;
  }
}