Aizu 0024

#include <iostream>
#include <stdio.h>
using namespace std;

int main()
{
    double v;
    double n;
    while((scanf("%lf",&v) != EOF)){
        n = v * v / 9.8 / 5.0 / 2 + 1.0;
        n = (int)n;
        if((n * 5 - 10) * 2 * 9.8 > v * v)
            cout << int(n - 1) << endl;
        else if((n * 5 - 5) * 2 * 9.8 > v * v)
            cout << int(n) << endl;
        else if((n * 5) * 2 * 9.8 > v * v)
            cout << int(n + 1) << endl;
        else
            cout << int(n) << endl;
    }
    return 0;
}