2017ACM/ICPC广西邀请赛 A Math Problem

解法：发现。。最多15个，那么。。暴力一下啦

#include <iostream>
#include <stdio.h>
#include <vector>
#include <string.h>
#include <map>
using namespace std;
struct Node{
    int x,y;
}node[123];
map<int,int>Mp;
long long n;
map<int,int>::iterator it;
int main(){
    while(~scanf("%lld",&n)){
        int sum=0;
        for(int i=1;i<=20;i++){
            long long x=1;
            for(int j=1;j<=i;j++){
                x*=i;
                if(x>=1e18+1){
                break;
                }
            }
            if(x<=n){
                sum++;
            }
        }
        cout<<sum<<endl;
    }
    return 0;
}