How many times the number \textbf{7} in consecutive positive integers from \textbf{A} to \textbf{B}? \InputFile The single line contains two positive integers \textbf{A} and \textbf{B} (\textbf{1 }≤\textbf{ A, B }≤\textbf{ 10^9}). \OutputFile A single number - the number of digits in seven consecutive positive integers from \textbf{A} to \textbf{B}.