factorialcalculator.cpp

#include <bits/stdc++.h>
using namespace std;

typedef long double ld;

const ld EPS = 1e-9;

int main() {
  int n; cin >> n;
  ld coef = 1; int expo = 0;
  for (ld i = 1; i <= n; i++) {
    coef *= i;
    while (!(coef < 10.0 - EPS)) {
      coef /= 10.0;
      expo++;
    }
  }
  cout << fixed << setprecision(9) << coef << "e+" << expo << '\n';
}