#include <iostream>
#include <stdio.h>
#include <vector>
#include <cctype>
#include <stdlib.h>
#include <numeric>
#include <string.h>
#include <algorithm>
#include <cmath>
#include <queue>
#include <stack>
#include <iterator>
#include <set>

using namespace std;

#define FOR(i, a, b) for (int i = (a) ; i < (b); i++)
#define sz size()
#define pb push_back
#define clean(t) memset ((t) , -1, sizeof(t))
#define VI vector <int>
#define VS vector <string>
#define cinput(n) scanf("%d", &n)


int main()
{
    int n;
    double a;
    VI ans;
    while(cin >> n)
    {
        if (n == 1) {ans.pb(1); continue; }
        if (n == 0) goto end;
        a = log(n)/log(2);
        if ( a == (int ) a) ans.pb(a);
        else ans.pb((int) a+1);

    }

    end:;

    int q;
    FOR(q, 0, ans.sz)
    {
        cout << ans[q] << endl;
    }

    return 0;
}


What's Wrong?? Plz some1 tell me..

Got AC..