import sys
input = sys.stdin.readline  # "\n"を含む

def solve(n):
    # j = 0 -> i+j+k = n-1
    # j = 1 -> i+j+k = n+1
    res = 0
    for j in range(2, 1<<10):
        # i = 0 -> i+j+k = n-1
        # i = 1 -> i+j+k = n
        i = 2
        while n - i**j >= 0:
            i += 1

        if i == 2:
            break

        i -= 1
        res = max(res, i**j - i - j)

    if res <= 1:
        return n - 1
    else:
        return n - res

def main():
    n = int(input())
    res = solve(n)
    print(res)

if __name__ == "__main__":
    main()