def main():
    n = input()
    n = int(n)
    # as multiple as possible

    i,j,k = 0,2,0

    for a in range(0,10**10): # fix range
        if n <= a**2:
            i = a-1
            break
    
    k = n - i**j
    
    return print(i+j+k)


if __name__ == "__main__":
    main()