#include <iostream>

using lint = long long;

void solve() {
    lint n;
    std::cin >> n;

    lint ok = 0, ng = 1 << 30;
    while (ng - ok > 1) {
        auto mid = (ok + ng) / 2;
        if (mid * mid <= n) {
            ok = mid;
        } else {
            ng = mid;
        }
    }

    std::cout << ok + n / ng << "\n";
}

int main() {
    std::cin.tie(nullptr);
    std::ios::sync_with_stdio(false);

    solve();

    return 0;
}