One beautiful July morning a terrible thing happened in Mainframe: a mean virus Megabyte somehow got access to the memory of his not less mean sister Hexadecimal. He loaded there a huge amount of n different natural numbers from 1 to n to obtain total control over her energy.

But his plan failed. The reason for this was very simple: Hexadecimal didn't perceive any information, apart from numbers written in binary format. This means that if a number in a decimal representation contained characters apart from 0 and 1, it was not stored in the memory. Now Megabyte wants to know, how many numbers were loaded successfully.

Input

Input data contains the only number n (1 ≤ n ≤ 109).

Output

Output the only number — answer to the problem.

Examples

Input

10


Output

2

Note

For n = 10 the answer includes numbers 1 and 10.
s=[1,10,11,100,101,110,111,1000,1001,1010,1011,1100,1101,1110,1111,10000,10001,10010,10011,10100,10101,10110,10111,11000,11001,11010,11011,11100,11101,11110,11111,100000,100001,100010,100011,100100,100101,100110,100111,101000,101001,101010,101011,101100,101101,101110,101111,110000,110001,110010,110011,110100,110101,110110,110111,111000,111001,111010,111011,111100,111101,111110,111111,1000000,1000001,1000010,1000011,1000100,1000101,1000110,1000111,1001000,1001001,1001010,1001011,1001100,1001101,1001110,1001111,1010000,1010001,1010010,1010011,1010100,1010101,1010110,1010111,1011000,1011001,1011010,1011011,1011100,1011101,1011110,1011111,1100000,1100001,1100010,1100011,1100100,1100101,1100110,1100111,1101000,1101001,1101010,1101011,1101100,1101101,1101110,1101111,1110000,1110001,1110010,1110011,1110100,1110101,1110110,1110111,1111000,1111001,1111010,1111011,1111100,1111101,1111110,1111111,10000000,10000001,10000010,10000011,10000100,10000101,10000110,10000111,10001000,10001001,10001010,10001011,10001100,10001101,10001110,10001111,10010000,10010001,10010010,10010011,10010100,10010101,10010110,10010111,10011000,10011001,10011010,10011011,10011100,10011101,10011110,10011111,10100000,10100001,10100010,10100011,10100100,10100101,10100110,10100111,10101000,10101001,10101010,10101011,10101100,10101101,10101110,10101111,10110000,10110001,10110010,10110011,10110100,10110101,10110110,10110111,10111000,10111001,10111010,10111011,10111100,10111101,10111110,10111111,11000000,11000001,11000010,11000011,11000100,11000101,11000110,11000111,11001000,11001001,11001010,11001011,11001100,11001101,11001110,11001111,11010000,11010001,11010010,11010011,11010100,11010101,11010110,11010111,11011000,11011001,11011010,11011011,11011100,11011101,11011110,11011111,11100000,11100001,11100010,11100011,11100100,11100101,11100110,11100111,11101000,11101001,11101010,11101011,11101100,11101101,11101110,11101111,11110000,11110001,11110010,11110011,11110100,11110101,11110110,11110111,11111000,11111001,11111010,11111011,11111100,11111101,11111110,11111111,100000000,100000001,100000010,100000011,100000100,100000101,100000110,100000111,100001000,100001001,100001010,100001011,100001100,100001101,100001110,100001111,100010000,100010001,100010010,100010011,100010100,100010101,100010110,100010111,100011000,100011001,100011010,100011011,100011100,100011101,100011110,100011111,100100000,100100001,100100010,100100011,100100100,100100101,100100110,100100111,100101000,100101001,100101010,100101011,100101100,100101101,100101110,100101111,100110000,100110001,100110010,100110011,100110100,100110101,100110110,100110111,100111000,100111001,100111010,100111011,100111100,100111101,100111110,100111111,101000000,101000001,101000010,101000011,101000100,101000101,101000110,101000111,101001000,101001001,101001010,101001011,101001100,101001101,101001110,101001111,101010000,101010001,101010010,101010011,101010100,101010101,101010110,101010111,101011000,101011001,101011010,101011011,101011100,101011101,101011110,101011111,101100000,101100001,101100010,101100011,101100100,101100101,101100110,101100111,101101000,101101001,101101010,101101011,101101100,101101101,101101110,101101111,101110000,101110001,101110010,101110011,101110100,101110101,101110110,101110111,101111000,101111001,101111010,101111011,101111100,101111101,101111110,101111111,110000000,110000001,110000010,110000011,110000100,110000101,110000110,110000111,110001000,110001001,110001010,110001011,110001100,110001101,110001110,110001111,110010000,110010001,110010010,110010011,110010100,110010101,110010110,110010111,110011000,110011001,110011010,110011011,110011100,110011101,110011110,110011111,110100000,110100001,110100010,110100011,110100100,110100101,110100110,110100111,110101000,110101001,110101010,110101011,110101100,110101101,110101110,110101111,110110000,110110001,110110010,110110011,110110100,110110101,110110110,110110111,110111000,110111001,110111010,110111011,110111100,110111101,110111110,110111111,111000000,111000001,111000010,111000011,111000100,111000101,111000110,111000111,111001000,111001001,111001010,111001011,111001100,111001101,111001110,111001111,111010000,111010001,111010010,111010011,111010100,111010101,111010110,111010111,111011000,111011001,111011010,111011011,111011100,111011101,111011110,111011111,111100000,111100001,111100010,111100011,111100100,111100101,111100110,111100111,111101000,111101001,111101010,111101011,111101100,111101101,111101110,111101111,111110000,111110001,111110010,111110011,111110100,111110101,111110110,111110111,111111000,111111001,111111010,111111011,111111100,111111101,111111110,111111111,1000000000,1000000001,1000000010,1000000011,1000000100,1000000101,1000000110,1000000111,1000001000,1000001001,1000001010,1000001011,1000001100,1000001101,1000001110,1000001111,1000010000,1000010001,1000010010,1000010011,1000010100,1000010101,1000010110,1000010111,1000011000,1000011001,1000011010,1000011011,1000011100,1000011101,1000011110,1000011111,1000100000,1000100001,1000100010,1000100011,1000100100,1000100101,1000100110,1000100111,1000101000,1000101001,1000101010,1000101011,1000101100,1000101101,1000101110,1000101111,1000110000,1000110001,1000110010,1000110011,1000110100,1000110101,1000110110,1000110111,1000111000,1000111001,1000111010,1000111011,1000111100,1000111101,1000111110,1000111111,1001000000,1001000001,1001000010,1001000011,1001000100,1001000101,1001000110,1001000111,1001001000,1001001001,1001001010,1001001011,1001001100,1001001101,1001001110,1001001111,1001010000,1001010001,1001010010,1001010011,1001010100,1001010101,1001010110,1001010111,1001011000,1001011001,1001011010,1001011011,1001011100,1001011101,1001011110,1001011111,1001100000,1001100001,1001100010,1001100011,1001100100,1001100101,1001100110,1001100111,1001101000,1001101001,1001101010,1001101011,1001101100,1001101101,1001101110,1001101111,1001110000,1001110001,1001110010,1001110011,1001110100,1001110101,1001110110,1001110111,1001111000,1001111001,1001111010,1001111011,1001111100,1001111101,1001111110,1001111111,1010000000,1010000001,1010000010,1010000011,1010000100,1010000101,1010000110,1010000111,1010001000,1010001001,1010001010,1010001011,1010001100,1010001101,1010001110,1010001111,1010010000,1010010001,1010010010,1010010011,1010010100,1010010101,1010010110,1010010111,1010011000,1010011001,1010011010,1010011011,1010011100,1010011101,1010011110,1010011111,1010100000,1010100001,1010100010,1010100011,1010100100,1010100101,1010100110,1010100111,1010101000,1010101001,1010101010,1010101011,1010101100,1010101101,1010101110,1010101111,1010110000,1010110001,1010110010,1010110011,1010110100,1010110101,1010110110,1010110111,1010111000,1010111001,1010111010,1010111011,1010111100,1010111101,1010111110,1010111111,1011000000,1011000001,1011000010,1011000011,1011000100,1011000101,1011000110,1011000111,1011001000,1011001001,1011001010,1011001011,1011001100,1011001101,1011001110,1011001111,1011010000,1011010001,1011010010,1011010011,1011010100,1011010101,1011010110,1011010111,1011011000,1011011001,1011011010,1011011011,1011011100,1011011101,1011011110,1011011111,1011100000,1011100001,1011100010,1011100011,1011100100,1011100101,1011100110,1011100111,1011101000,1011101001,1011101010,1011101011,1011101100,1011101101,1011101110,1011101111,1011110000,1011110001,1011110010,1011110011,1011110100,1011110101,1011110110,1011110111,1011111000,1011111001,1011111010,1011111011,1011111100,1011111101,1011111110,1011111111,1100000000,1100000001,1100000010,1100000011,1100000100,1100000101,1100000110,1100000111,1100001000,1100001001,1100001010,1100001011,1100001100,1100001101,1100001110,1100001111,1100010000,1100010001,1100010010,1100010011,1100010100,1100010101,1100010110,1100010111,1100011000,1100011001,1100011010,1100011011,1100011100,1100011101,1100011110,1100011111,1100100000,1100100001,1100100010,1100100011,1100100100,1100100101,1100100110,1100100111,1100101000,1100101001,1100101010,1100101011,1100101100,1100101101,1100101110,1100101111,1100110000,1100110001,1100110010,1100110011,1100110100,1100110101,1100110110,1100110111,1100111000,1100111001,1100111010,1100111011,1100111100,1100111101,1100111110,1100111111,1101000000,1101000001,1101000010,1101000011,1101000100,1101000101,1101000110,1101000111,1101001000,1101001001,1101001010,1101001011,1101001100,1101001101,1101001110,1101001111,1101010000,1101010001,1101010010,1101010011,1101010100,1101010101,1101010110,1101010111,1101011000,1101011001,1101011010,1101011011,1101011100,1101011101,1101011110,1101011111,1101100000,1101100001,1101100010,1101100011,1101100100,1101100101,1101100110,1101100111,1101101000,1101101001,1101101010,1101101011,1101101100,1101101101,1101101110,1101101111,1101110000,1101110001,1101110010,1101110011,1101110100,1101110101,1101110110,1101110111,1101111000,1101111001,1101111010,1101111011,1101111100,1101111101,1101111110,1101111111,1110000000,1110000001,1110000010,1110000011,1110000100,1110000101,1110000110,1110000111,1110001000,1110001001,1110001010,1110001011,1110001100,1110001101,1110001110,1110001111,1110010000,1110010001,1110010010,1110010011,1110010100,1110010101,1110010110,1110010111,1110011000,1110011001,1110011010,1110011011,1110011100,1110011101,1110011110,1110011111,1110100000,1110100001,1110100010,1110100011,1110100100,1110100101,1110100110,1110100111,1110101000,1110101001,1110101010,1110101011,1110101100,1110101101,1110101110,1110101111,1110110000,1110110001,1110110010,1110110011,1110110100,1110110101,1110110110,1110110111,1110111000,1110111001,1110111010,1110111011,1110111100,1110111101,1110111110,1110111111,1111000000,1111000001,1111000010,1111000011,1111000100,1111000101,1111000110,1111000111,1111001000,1111001001,1111001010,1111001011,1111001100,1111001101,1111001110,1111001111,1111010000,1111010001,1111010010,1111010011,1111010100,1111010101,1111010110,1111010111,1111011000,1111011001,1111011010,1111011011,1111011100,1111011101,1111011110,1111011111,1111100000,1111100001,1111100010,1111100011,1111100100,1111100101,1111100110,1111100111,1111101000,1111101001,1111101010,1111101011,1111101100,1111101101,1111101110,1111101111,1111110000,1111110001,1111110010,1111110011,1111110100,1111110101,1111110110,1111110111,1111111000,1111111001,1111111010,1111111011,1111111100,1111111101,1111111110,1111111111]
n=input()
print (len([i for i in s if i<=n]))