C++ :

#include <iostream>  
using namespace std;  
int main(){  
    int i = 1,n,x;
    double s = 0;
    cin>>x;
     while(s <= x){ 
   s = s + 1.0 / i;
   i++;
}
cout<<i - 1<<endl;
    return 0;  
  } 

Python :

x = int(input())
s = 0
i = 1
while True:
    s += 1 / i
    if s > x:
        print(i)
        break
    i += 1