Sicily 1119. Factstone Benchmark

1119. Factstone Benchmark

Time Limit: 1sec    Memory Limit:32MB

Description

Amtel has announced that it will release a 128-bit computer chip by 2010, a 256-bit computer by 2020, and so on, continuing its strategy of doubling the word-size every ten years. (Amtel released a 64-bit computer in 2000, a 32-bit computer in 1990, a 16-bit
computer in 1980, an 8-bit computer in 1970, and a 4-bit computer, its first, in 1960.)

Amtel will use a new benchmark - the Factstone - to advertise the vastly improved capacity of its new chips. The Factstone rating is defined to be the largest integer n such that n! can be represented as an unsigned integer
in a computer word.

Input

Given a year 1960 ≤ y ≤ 2160, what will be the Factstone rating of Amtel‘s most recently released chip?

Output

There are several test cases. For each test case, there is one line of input containing y. A line containing 0 follows the last test case. For each test case, output a line giving the Factstone rating.

Sample Input

 Copy sample input to clipboard

1960
1981
0

Sample Output

3
8

Status

Submit

Source Code

// 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;
}