Sicily 1119. Factstone Benchmark

// Problem#: 1119
// Submission#: 3731244
// The source code is licensed under Creative Commons Attribution-NonCommercial-ShareAlike 3.0 Unported License
// URI: http://creativecommons.org/licenses/by-nc-sa/3.0/
// All Copyright reserved by Informatic Lab of Sun Yat-sen University
#include<iostream>
#include<cmath>
#include<cstdio>
#include<algorithm>
int main(){
    int year;
    int endflag;
    int n;
    double sum;
    while(scanf("%d", &year) && year){
        endflag = pow(2, (year - 1960) / 10 + 2);
        n = 2;
        sum = 0;
        while(sum <= endflag){
            sum += log(n) / log(2);
            ++n;
        }
        printf("%d\n", n - 2);
    }
    return 0;
}