MIDI_CodeJam.2.Painus_kelias

#include <iostream>
#include <stdio.h>
using namespace std;
int main()
{
    unsigned long long int a, b=1, z=1, j=2;
    cin>>a;
    while(b<a)
    {
        z+=1;
        b=b*j;
        j+=1;
    }
    cout<<z<<endl;
    return 0;
}