#include <iostream>
#include <algorithm>
#include <map>
#include <set>
#include <queue>
#include <stack>
#include <numeric>
#include <bitset>
#include <cmath>

static const int MOD = 1000000007;
using ll = long long;
using u32 = unsigned;
using u64 = unsigned long long;
using namespace std;

template<class T> constexpr T INF = ::numeric_limits<T>::max()/32*15+208;
u64 Isqrt(u64 const &x){
    u64 ret = (u64)sqrtl(x);
    while(ret > 0 && ret*ret > x) --ret;
    while(x - ret*ret > 2*ret) ++ret;
    return ret;
}

int main() {
    int n;
    cin >> n;
    ll vval = Isqrt(n);
    cout << n/(vval+1)+vval << "\n";

    return 0;
}