## https://yukicoder.me/problems/no/1162

import math

def main():
    N = int(input())
    if N == 1:
        print(1)
        return

    low = 0
    high = int(math.sqrt(N)) * 2
    while high - low > 1:
        mid = (high + low) // 2
        if mid ** 2 <= N:
            low = mid
        else:
            high = mid
    if high ** 2 <= N:
        v = high
    else:
        v = low

    # 本格的な計算
    n = v + 1
    m = N // n
    answer = m

    low = max(1, v - 10 ** 5)
    high = v
    a_set = set()
    for i in reversed(range(low, v + 1)):
        l = N // i
        if l > m:
            a_set.add(l)
    
    answer += low - 1 + len(a_set)
    print(answer)


    
        
    




if __name__ == "__main__":
    main()