1355. Solving inequalities

Title description

Known inequality 1! +2! +3! +...+m! ‹N, please program to calculate the value of n specified by the user and output the integer solution of m that satisfies the inequality.

enter

Enter an integer n, where n is a positive integer in the range of int.

Output

Output the value range of m, see the output sample for the specific format.

Sample input

2000000000

Sample output

m<=12

Code content

#include<iostream>
using namespace std; 

long long  jiec(long long  n)
{
    
    
    long long i,a=1;
    for(i=1;i<=n;i++)
        a=a*i;
    return a;
}

int main()
{
    
    
	long long  n,i,j,sum=0;
	cin>>n;
	for(i=0;n>=0;i++)
    {
    
    
    	n=n-jiec(i);
    	j=i;
    }
    cout<<"m<="<<j-1;
	return 0;
}